diff --git a/docs/CONTRIBUTORS.rst b/docs/CONTRIBUTORS.rst
index 3be2b607b6..cc2704f269 100644
--- a/docs/CONTRIBUTORS.rst
+++ b/docs/CONTRIBUTORS.rst
@@ -116,6 +116,14 @@ dependencies must already be installed (see above).
     $ cd tests
     $ python aggregate_tests.py
 
+Individual tests can also be executed. Optional '-v' flags can be added to
+increase log level up to DEBUG ('-vvvv').
+::
+
+    $ python test_updater.py # run a specific test file
+    $ python test_updater.py TestUpdater.test_4_refresh # run a specific test
+    $ python test_updater.py -vvvv TestUpdater.test_4_refresh # run test with DEBUG log level
+
 
 To run the tests and measure their code coverage, the aggregation script can be
 invoked with the ``coverage`` tool (requires installation of ``coverage``, e.g.
diff --git a/tests/test_api.py b/tests/test_api.py
index b2329bf780..00733132e9 100644
--- a/tests/test_api.py
+++ b/tests/test_api.py
@@ -17,6 +17,8 @@
 from datetime import datetime, timedelta
 from dateutil.relativedelta import relativedelta
 
+import utils
+
 # TODO: Remove case handling when fully dropping support for versions >= 3.6
 IS_PY_VERSION_SUPPORTED = sys.version_info >= (3, 6)
 
@@ -258,4 +260,5 @@ def test_metadata_timestamp(self):
 
 # Run unit test.
 if __name__ == '__main__':
+    utils.configure_test_logging(sys.argv)
     unittest.main()
diff --git a/tests/test_arbitrary_package_attack.py b/tests/test_arbitrary_package_attack.py
index 6ce0ed691d..640b5596b1 100755
--- a/tests/test_arbitrary_package_attack.py
+++ b/tests/test_arbitrary_package_attack.py
@@ -44,6 +44,7 @@
 import subprocess
 import logging
 import unittest
+import sys
 
 import tuf
 import tuf.formats
@@ -302,4 +303,5 @@ def test_with_tuf_and_metadata_tampering(self):
 
 
 if __name__ == '__main__':
+  utils.configure_test_logging(sys.argv)
   unittest.main()
diff --git a/tests/test_developer_tool.py b/tests/test_developer_tool.py
index 27ceeb76e5..6867104b60 100755
--- a/tests/test_developer_tool.py
+++ b/tests/test_developer_tool.py
@@ -26,6 +26,7 @@
 import logging
 import tempfile
 import shutil
+import sys
 
 import tuf
 import tuf.log
@@ -40,6 +41,8 @@
 from tuf.developer_tool import METADATA_DIRECTORY_NAME
 from tuf.developer_tool import TARGETS_DIRECTORY_NAME
 
+import utils
+
 logger = logging.getLogger(__name__)
 
 developer_tool.disable_console_log_messages()
@@ -423,4 +426,5 @@ def test_write(self):
 
 
 if __name__ == '__main__':
+  utils.configure_test_logging(sys.argv)
   unittest.main()
diff --git a/tests/test_download.py b/tests/test_download.py
index 2f97048ac6..e9f1429e1c 100755
--- a/tests/test_download.py
+++ b/tests/test_download.py
@@ -391,4 +391,5 @@ def popen_python(command_arg_list):
 
 # Run unit test.
 if __name__ == '__main__':
+  utils.configure_test_logging(sys.argv)
   unittest.main()
diff --git a/tests/test_endless_data_attack.py b/tests/test_endless_data_attack.py
index 14452a6b85..b1977ec5b0 100755
--- a/tests/test_endless_data_attack.py
+++ b/tests/test_endless_data_attack.py
@@ -47,6 +47,7 @@
 import subprocess
 import logging
 import unittest
+import sys
 
 import tuf
 import tuf.formats
@@ -290,4 +291,5 @@ def test_with_tuf(self):
 
 
 if __name__ == '__main__':
+  utils.configure_test_logging(sys.argv)
   unittest.main()
diff --git a/tests/test_exceptions.py b/tests/test_exceptions.py
deleted file mode 100755
index d3e54afb25..0000000000
--- a/tests/test_exceptions.py
+++ /dev/null
@@ -1,59 +0,0 @@
-#!/usr/bin/env python
-
-# Copyright 2014 - 2017, New York University and the TUF contributors
-# SPDX-License-Identifier: MIT OR Apache-2.0
-
-"""
-<Program Name>
-  test_exceptions.py
-
-<Author>
-  Vladimir Diaz
-
-<Started>
-  July 13, 2017.
-
-<Copyright>
-  See LICENSE-MIT OR LICENSE for licensing information.
-
-<Purpose>
-  Test cases for exceptions.py (mainly the exceptions defined there).
-"""
-
-# Help with Python 3 compatibility, where the print statement is a function, an
-# implicit relative import is invalid, and the '/' operator performs true
-# division.  Example:  print 'hello world' raises a 'SyntaxError' exception.
-from __future__ import print_function
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import unicode_literals
-
-import unittest
-import logging
-
-import tuf.exceptions
-
-logger = logging.getLogger(__name__)
-
-class TestExceptions(unittest.TestCase):
-  def setUp(self):
-    pass
-
-
-  def tearDown(self):
-    pass
-
-
-  def test_bad_signature_error(self):
-    bad_signature_error = tuf.exceptions.BadSignatureError('bad sig')
-    logger.error(bad_signature_error)
-
-
-  def test_bad_hash_error(self):
-    bad_hash_error = tuf.exceptions.BadHashError('1234', '5678')
-    logger.error(bad_hash_error)
-
-
-# Run the unit tests.
-if __name__ == '__main__':
-  unittest.main()
diff --git a/tests/test_extraneous_dependencies_attack.py b/tests/test_extraneous_dependencies_attack.py
index 421b4983a6..c67a6a25a4 100755
--- a/tests/test_extraneous_dependencies_attack.py
+++ b/tests/test_extraneous_dependencies_attack.py
@@ -50,6 +50,7 @@
 import subprocess
 import logging
 import unittest
+import sys
 
 import tuf.formats
 import tuf.log
@@ -234,4 +235,5 @@ def test_with_tuf(self):
 
 
 if __name__ == '__main__':
+  utils.configure_test_logging(sys.argv)
   unittest.main()
diff --git a/tests/test_formats.py b/tests/test_formats.py
index 7b3116e7f4..9faa017633 100755
--- a/tests/test_formats.py
+++ b/tests/test_formats.py
@@ -30,10 +30,13 @@
 
 import unittest
 import datetime
+import sys
 
 import tuf
 import tuf.formats
 
+import utils
+
 import securesystemslib
 import six
 
@@ -968,4 +971,5 @@ def test_encode_canonical(self):
 
 # Run unit test.
 if __name__ == '__main__':
+  utils.configure_test_logging(sys.argv)
   unittest.main()
diff --git a/tests/test_indefinite_freeze_attack.py b/tests/test_indefinite_freeze_attack.py
index 80ef4f7f02..c94b288a02 100755
--- a/tests/test_indefinite_freeze_attack.py
+++ b/tests/test_indefinite_freeze_attack.py
@@ -53,6 +53,7 @@
 import subprocess
 import logging
 import unittest
+import sys
 
 import tuf.formats
 import tuf.log
@@ -504,4 +505,5 @@ def test_with_tuf(self):
 
 
 if __name__ == '__main__':
+  utils.configure_test_logging(sys.argv)
   unittest.main()
diff --git a/tests/test_init.py b/tests/test_init.py
deleted file mode 100755
index 03dfc65bdb..0000000000
--- a/tests/test_init.py
+++ /dev/null
@@ -1,75 +0,0 @@
-#!/usr/bin/env python
-
-# Copyright 2015 - 2017, New York University and the TUF contributors
-# SPDX-License-Identifier: MIT OR Apache-2.0
-
-"""
-<Program Name>
-  test_init.py
-
-<Author>
-  Vladimir Diaz
-
-<Started>
-  March 30, 2015.
-
-<Copyright>
-  See LICENSE-MIT OR LICENSE for licensing information.
-
-<Purpose>
-  Test cases for __init__.py (mainly the exceptions defined there).
-"""
-
-# Help with Python 3 compatibility, where the print statement is a function, an
-# implicit relative import is invalid, and the '/' operator performs true
-# division.  Example:  print 'hello world' raises a 'SyntaxError' exception.
-from __future__ import print_function
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import unicode_literals
-
-import unittest
-import logging
-
-import tuf
-import tuf.exceptions
-import tuf.log
-
-import securesystemslib
-
-logger = logging.getLogger(__name__)
-
-class TestInit(unittest.TestCase):
-  def setUp(self):
-    pass
-
-
-  def tearDown(self):
-    pass
-
-
-  def test_bad_signature_error(self):
-    bad_signature_error = securesystemslib.exceptions.BadSignatureError('bad_role')
-    logger.error(bad_signature_error)
-
-
-  def test_slow_retrieval_error(self):
-    slow_signature_error = tuf.exceptions.SlowRetrievalError('bad_role')
-    logger.error(slow_signature_error)
-
-
-  def test_bad_hash_error(self):
-    bad_hash_error = securesystemslib.exceptions.BadHashError('01234', '56789')
-    logger.error(bad_hash_error)
-
-
-  def test_invalid_metadata_json_error(self):
-    format_error = securesystemslib.exceptions.FormatError('Improperly formatted JSON')
-    invalid_metadata_json_error = tuf.exceptions.InvalidMetadataJSONError(format_error)
-    logger.error(invalid_metadata_json_error)
-
-
-
-# Run the unit tests.
-if __name__ == '__main__':
-  unittest.main()
diff --git a/tests/test_key_revocation_integration.py b/tests/test_key_revocation_integration.py
index 1e72443aa0..8e7aade040 100755
--- a/tests/test_key_revocation_integration.py
+++ b/tests/test_key_revocation_integration.py
@@ -44,6 +44,7 @@
 import random
 import subprocess
 import unittest
+import sys
 
 import tuf
 import tuf.log
@@ -514,4 +515,5 @@ def _load_role_keys(keystore_directory):
 
 
 if __name__ == '__main__':
+  utils.configure_test_logging(sys.argv)
   unittest.main()
diff --git a/tests/test_keydb.py b/tests/test_keydb.py
index d9ef148d25..4d481bd776 100755
--- a/tests/test_keydb.py
+++ b/tests/test_keydb.py
@@ -30,6 +30,7 @@
 
 import unittest
 import logging
+import sys
 
 import tuf
 import tuf.formats
@@ -38,6 +39,8 @@
 import tuf.keydb
 import tuf.log
 
+import utils
+
 logger = logging.getLogger(__name__)
 
 
@@ -408,4 +411,5 @@ def test_create_keydb_from_root_metadata(self):
 
 # Run unit test.
 if __name__ == '__main__':
+  utils.configure_test_logging(sys.argv)
   unittest.main()
diff --git a/tests/test_log.py b/tests/test_log.py
index ad4aa37127..ea545ea12c 100755
--- a/tests/test_log.py
+++ b/tests/test_log.py
@@ -24,6 +24,7 @@
 import unittest
 import os
 import shutil
+import sys
 
 import tuf
 import tuf.log
@@ -32,6 +33,8 @@
 import securesystemslib
 import securesystemslib.util
 
+import utils
+
 from six.moves import reload_module
 
 # We explicitly create a logger which is a child of the tuf hierarchy,
@@ -46,10 +49,15 @@
 
 class TestLog(unittest.TestCase):
 
+  def setUp(self):
+    # store the current log level so it can be restored after the test
+    self._initial_level = logging.getLogger('tuf').level
 
   def tearDown(self):
     tuf.log.remove_console_handler()
     tuf.log.disable_file_logging()
+    logging.getLogger('tuf').level = self._initial_level
+
 
 
 
@@ -198,4 +206,5 @@ def test_disable_file_logging(self):
 
 # Run unit test.
 if __name__ == '__main__':
+  utils.configure_test_logging(sys.argv)
   unittest.main()
diff --git a/tests/test_mirrors.py b/tests/test_mirrors.py
index aa5efc7fb3..0c703ff37d 100755
--- a/tests/test_mirrors.py
+++ b/tests/test_mirrors.py
@@ -29,10 +29,13 @@
 from __future__ import unicode_literals
 
 import unittest
+import sys
 
 import tuf.mirrors as mirrors
 import tuf.unittest_toolbox as unittest_toolbox
 
+import utils
+
 import securesystemslib
 import securesystemslib.util
 import six
@@ -111,4 +114,5 @@ def test_get_list_of_mirrors(self):
 
 # Run the unittests
 if __name__ == '__main__':
+  utils.configure_test_logging(sys.argv)
   unittest.main()
diff --git a/tests/test_mix_and_match_attack.py b/tests/test_mix_and_match_attack.py
index f077cb6ed1..131af35a54 100755
--- a/tests/test_mix_and_match_attack.py
+++ b/tests/test_mix_and_match_attack.py
@@ -45,6 +45,7 @@
 import subprocess
 import logging
 import unittest
+import sys
 
 import tuf.exceptions
 import tuf.log
@@ -255,4 +256,5 @@ def test_with_tuf(self):
 
 
 if __name__ == '__main__':
+  utils.configure_test_logging(sys.argv)
   unittest.main()
diff --git a/tests/test_multiple_repositories_integration.py b/tests/test_multiple_repositories_integration.py
index d3c0c9717c..6db53682a0 100755
--- a/tests/test_multiple_repositories_integration.py
+++ b/tests/test_multiple_repositories_integration.py
@@ -37,6 +37,7 @@
 import shutil
 import unittest
 import json
+import sys
 
 import tuf
 import tuf.log
@@ -301,4 +302,5 @@ def test_repository_tool(self):
 
 
 if __name__ == '__main__':
+  utils.configure_test_logging(sys.argv)
   unittest.main()
diff --git a/tests/test_proxy_use.py b/tests/test_proxy_use.py
index 744880b78a..27e0988217 100644
--- a/tests/test_proxy_use.py
+++ b/tests/test_proxy_use.py
@@ -380,4 +380,5 @@ def popen_python(command_arg_list):
 
 # Run unit test.
 if __name__ == '__main__':
+  utils.configure_test_logging(sys.argv)
   unittest.main()
diff --git a/tests/test_replay_attack.py b/tests/test_replay_attack.py
index 1fdd8915d8..e8c862425b 100755
--- a/tests/test_replay_attack.py
+++ b/tests/test_replay_attack.py
@@ -46,6 +46,7 @@
 import subprocess
 import logging
 import unittest
+import sys
 
 import tuf.formats
 import tuf.log
@@ -338,4 +339,5 @@ def test_with_tuf(self):
 
 
 if __name__ == '__main__':
+  utils.configure_test_logging(sys.argv)
   unittest.main()
diff --git a/tests/test_repository_lib.py b/tests/test_repository_lib.py
index 4c449f4c97..0fa9a6aeee 100755
--- a/tests/test_repository_lib.py
+++ b/tests/test_repository_lib.py
@@ -37,6 +37,7 @@
 import shutil
 import unittest
 import copy
+import sys
 
 import tuf
 import tuf.formats
@@ -49,6 +50,8 @@
 import tuf.repository_lib as repo_lib
 import tuf.repository_tool as repo_tool
 
+import utils
+
 import securesystemslib
 import securesystemslib.exceptions
 import securesystemslib.rsa_keys
@@ -1057,4 +1060,5 @@ def test__remove_invalid_and_duplicate_signatures(self):
 
 # Run the test cases.
 if __name__ == '__main__':
+  utils.configure_test_logging(sys.argv)
   unittest.main()
diff --git a/tests/test_repository_tool.py b/tests/test_repository_tool.py
index bdea70d500..09095411b8 100755
--- a/tests/test_repository_tool.py
+++ b/tests/test_repository_tool.py
@@ -35,17 +35,19 @@
 import logging
 import tempfile
 import shutil
+import sys
 
 import tuf
 import tuf.log
 import tuf.formats
 import tuf.roledb
 import tuf.keydb
-
 import tuf.repository_tool as repo_tool
-import securesystemslib.exceptions
+
+import utils
 
 import securesystemslib
+import securesystemslib.exceptions
 import securesystemslib.storage
 
 logger = logging.getLogger(__name__)
@@ -2194,4 +2196,5 @@ def test_append_signature(self):
 
 # Run the test cases.
 if __name__ == '__main__':
+  utils.configure_test_logging(sys.argv)
   unittest.main()
diff --git a/tests/test_roledb.py b/tests/test_roledb.py
index f036c763fd..4bc4efb0c8 100755
--- a/tests/test_roledb.py
+++ b/tests/test_roledb.py
@@ -30,6 +30,7 @@
 
 import unittest
 import logging
+import sys
 
 import tuf
 import tuf.formats
@@ -37,6 +38,8 @@
 import tuf.exceptions
 import tuf.log
 
+import utils
+
 import securesystemslib
 import securesystemslib.keys
 
@@ -788,4 +791,5 @@ def tearDownModule():
 
 # Run the unit tests.
 if __name__ == '__main__':
+  utils.configure_test_logging(sys.argv)
   unittest.main()
diff --git a/tests/test_root_versioning_integration.py b/tests/test_root_versioning_integration.py
index a73c2ade73..ee6f143c34 100755
--- a/tests/test_root_versioning_integration.py
+++ b/tests/test_root_versioning_integration.py
@@ -30,6 +30,7 @@
 import tempfile
 import shutil
 import unittest
+import sys
 
 import tuf
 import tuf.log
@@ -39,6 +40,8 @@
 import tuf.keydb
 import tuf.repository_tool as repo_tool
 
+import utils
+
 import securesystemslib
 import securesystemslib.storage
 
@@ -227,4 +230,5 @@ def test_root_role_versioning(self):
 
 
 if __name__ == '__main__':
+  utils.configure_test_logging(sys.argv)
   unittest.main()
diff --git a/tests/test_sig.py b/tests/test_sig.py
index 1876c44a45..100c1368fa 100755
--- a/tests/test_sig.py
+++ b/tests/test_sig.py
@@ -32,6 +32,7 @@
 import unittest
 import logging
 import copy
+import sys
 
 import tuf
 import tuf.log
@@ -41,6 +42,8 @@
 import tuf.sig
 import tuf.exceptions
 
+import utils
+
 import securesystemslib
 import securesystemslib.keys
 
@@ -547,4 +550,5 @@ def test_signable_has_invalid_format(self):
 
 # Run unit test.
 if __name__ == '__main__':
+  utils.configure_test_logging(sys.argv)
   unittest.main()
diff --git a/tests/test_slow_retrieval_attack.py b/tests/test_slow_retrieval_attack.py
index 50e9b89e97..5273e16843 100755
--- a/tests/test_slow_retrieval_attack.py
+++ b/tests/test_slow_retrieval_attack.py
@@ -52,6 +52,7 @@
 import subprocess
 import logging
 import unittest
+import sys
 
 import tuf.log
 import tuf.client.updater as updater
@@ -60,6 +61,8 @@
 import tuf.roledb
 import tuf.keydb
 
+import utils
+
 import six
 
 logger = logging.getLogger(__name__)
@@ -322,4 +325,5 @@ def test_with_tuf_mode_2(self):
 
 
 if __name__ == '__main__':
+  utils.configure_test_logging(sys.argv)
   unittest.main()
diff --git a/tests/test_tutorial.py b/tests/test_tutorial.py
index e3102c66cc..83ee56404a 100644
--- a/tests/test_tutorial.py
+++ b/tests/test_tutorial.py
@@ -44,6 +44,8 @@
 
 from tuf.repository_tool import *   # part of TUTORIAL.md
 
+import utils
+
 import securesystemslib.exceptions
 
 from securesystemslib.formats import encode_canonical # part of TUTORIAL.md
@@ -416,4 +418,5 @@ def test_tutorial(self):
 
 # Run unit test.
 if __name__ == '__main__':
+  utils.configure_test_logging(sys.argv)
   unittest.main()
diff --git a/tests/test_unittest_toolbox.py b/tests/test_unittest_toolbox.py
index 10b68202b9..308c0a4c80 100755
--- a/tests/test_unittest_toolbox.py
+++ b/tests/test_unittest_toolbox.py
@@ -31,9 +31,12 @@
 import unittest
 import logging
 import shutil
+import sys
 
 import tuf.unittest_toolbox as unittest_toolbox
 
+import utils
+
 logger = logging.getLogger(__name__)
 
 
@@ -55,4 +58,5 @@ def test_tear_down_already_deleted_dir(self):
 
 # Run the unit tests.
 if __name__ == '__main__':
+  utils.configure_test_logging(sys.argv)
   unittest.main()
diff --git a/tests/test_updater.py b/tests/test_updater.py
index 3ea0206adf..5f2f3c3ee4 100644
--- a/tests/test_updater.py
+++ b/tests/test_updater.py
@@ -58,6 +58,7 @@
 import random
 import subprocess
 import errno
+import sys
 import unittest
 
 import tuf
@@ -2178,4 +2179,5 @@ def _load_role_keys(keystore_directory):
 
 
 if __name__ == '__main__':
+  utils.configure_test_logging(sys.argv)
   unittest.main()
diff --git a/tests/test_updater_root_rotation_integration.py b/tests/test_updater_root_rotation_integration.py
index 71cdc39e0a..84ce59ac63 100755
--- a/tests/test_updater_root_rotation_integration.py
+++ b/tests/test_updater_root_rotation_integration.py
@@ -49,6 +49,7 @@
 import subprocess
 import unittest
 import filecmp
+import sys
 
 import tuf
 import tuf.log
@@ -643,4 +644,5 @@ def _load_role_keys(keystore_directory):
 
 
 if __name__ == '__main__':
+  utils.configure_test_logging(sys.argv)
   unittest.main()
diff --git a/tests/utils.py b/tests/utils.py
index 02b0820c3e..d0ad75d5b8 100644
--- a/tests/utils.py
+++ b/tests/utils.py
@@ -20,11 +20,14 @@
   Provide common utilities for TUF tests
 """
 
+import argparse
 import errno
 import logging
 import socket
 import time
 
+import tuf.log
+
 logger = logging.getLogger(__name__)
 
 try:
@@ -74,3 +77,23 @@ def wait_for_server(host, port, timeout=10):
     raise TimeoutError
 
 
+def configure_test_logging(argv):
+  # parse arguments but only handle '-v': argv may contain 
+  # other things meant for unittest argument parser
+  parser = argparse.ArgumentParser(add_help=False)
+  parser.add_argument('-v', '--verbose', action='count', default=0)
+  args, _ = parser.parse_known_args(argv)
+  
+  if args.verbose <= 1:
+    # 0 and 1 both mean ERROR: this way '-v' makes unittest print test
+    # names without increasing log level
+    loglevel = logging.ERROR
+  elif args.verbose == 2:
+    loglevel = logging.WARNING
+  elif args.verbose == 3:
+    loglevel = logging.INFO
+  else:
+    loglevel = logging.DEBUG
+
+  logging.basicConfig(level=loglevel)
+  tuf.log.set_log_level(loglevel)
diff --git a/tuf/client/updater.py b/tuf/client/updater.py
index 564e285efd..a595a62953 100755
--- a/tuf/client/updater.py
+++ b/tuf/client/updater.py
@@ -960,8 +960,8 @@ def _import_delegations(self, parent_role):
           pass
 
         except (securesystemslib.exceptions.FormatError, securesystemslib.exceptions.Error):
-          logger.exception('Invalid key for keyid: ' + repr(keyid) + '.')
-          logger.error('Aborting role delegation for parent role ' + parent_role + '.')
+          logger.warning('Invalid key: ' + repr(keyid) + '. Aborting role ' +
+              'delegation for parent role \'' + parent_role + '\'.')
           raise
 
       else:
@@ -981,7 +981,7 @@ def _import_delegations(self, parent_role):
         logger.warning('Role already exists: ' + rolename)
 
       except Exception:
-        logger.exception('Failed to add delegated role: ' + repr(rolename) + '.')
+        logger.warning('Failed to add delegated role: ' + repr(rolename) + '.')
         raise
 
 
@@ -1142,12 +1142,10 @@ def neither_403_nor_404(mirror_error):
           # Otherwise, reraise the error, because it is not a simple HTTP
           # error.
           if neither_403_nor_404(mirror_error):
-            logger.exception('Misc error for root version '+str(next_version))
+            logger.info('Misc error for root version ' + str(next_version))
             raise
           else:
-            # Calling this function should give us a detailed stack trace
-            # including an HTTP error code, if any.
-            logger.exception('HTTP error for root version '+str(next_version))
+            logger.debug('HTTP error for root version ' + str(next_version))
         # If we are here, then we ran into only 403 / 404 errors, which are
         # good reasons to suspect that the next root metadata file does not
         # exist.
@@ -1635,7 +1633,7 @@ def _get_metadata_file(self, metadata_role, remote_filename,
 
       except Exception as exception:
         # Remember the error from this mirror, and "reset" the target file.
-        logger.exception('Update failed from ' + file_mirror + '.')
+        logger.debug('Update failed from ' + file_mirror + '.')
         file_mirror_errors[file_mirror] = exception
         file_object = None
 
@@ -1646,7 +1644,7 @@ def _get_metadata_file(self, metadata_role, remote_filename,
       return file_object
 
     else:
-      logger.error('Failed to update ' + repr(remote_filename) + ' from all'
+      logger.debug('Failed to update ' + repr(remote_filename) + ' from all'
         ' mirrors: ' + repr(file_mirror_errors))
       raise tuf.exceptions.NoWorkingMirrorError(file_mirror_errors)
 
@@ -1725,7 +1723,7 @@ def _get_file(self, filepath, verify_file_function, file_type, file_length,
 
       except Exception as exception:
         # Remember the error from this mirror, and "reset" the target file.
-        logger.exception('Update failed from ' + file_mirror + '.')
+        logger.debug('Update failed from ' + file_mirror + '.')
         file_mirror_errors[file_mirror] = exception
         file_object = None
 
@@ -1736,7 +1734,7 @@ def _get_file(self, filepath, verify_file_function, file_type, file_length,
       return file_object
 
     else:
-      logger.error('Failed to update ' + repr(filepath) + ' from'
+      logger.debug('Failed to update ' + repr(filepath) + ' from'
           ' all mirrors: ' + repr(file_mirror_errors))
       raise tuf.exceptions.NoWorkingMirrorError(file_mirror_errors)
 
@@ -1988,7 +1986,7 @@ def _update_metadata_if_changed(self, metadata_role,
       # need to, but we need to check the trust implications of the current
       # implementation.
       self._delete_metadata(metadata_role)
-      logger.error('Metadata for ' + repr(metadata_role) + ' cannot'
+      logger.warning('Metadata for ' + repr(metadata_role) + ' cannot'
           ' be updated.')
       raise
 
@@ -2404,8 +2402,6 @@ def _ensure_not_expired(self, metadata_object, metadata_rolename):
     if expires_timestamp < current_time:
       message = 'Metadata '+repr(metadata_rolename)+' expired on ' + \
         expires_datetime.ctime() + ' (UTC).'
-      logger.error(message)
-
       raise tuf.exceptions.ExpiredMetadataError(message)
 
 
@@ -2755,7 +2751,6 @@ def get_one_valid_targetinfo(self, target_filepath):
 
     # Raise an exception if the target information could not be retrieved.
     if target is None:
-      logger.error(repr(target_filepath) + ' not found.')
       raise tuf.exceptions.UnknownTargetError(repr(target_filepath) + ' not'
           ' found.')
 
@@ -3111,7 +3106,7 @@ def remove_obsolete_targets(self, destination_directory):
                     ' removed.')
 
                 else:
-                  logger.error(str(e))
+                  logger.warning('Failed to remove obsolete target: ' + str(e) )
 
             else:
               logger.debug('Skipping: ' + repr(target) + '.  It is still'
diff --git a/tuf/download.py b/tuf/download.py
index 7065fe1c03..f75e7cdf17 100755
--- a/tuf/download.py
+++ b/tuf/download.py
@@ -278,7 +278,7 @@ def _download_file(url, required_length, STRICT_REQUIRED_LENGTH=True):
   except Exception:
     # Close 'temp_file'.  Any written data is lost.
     temp_file.close()
-    logger.exception('Could not download URL: ' + repr(url))
+    logger.debug('Could not download URL: ' + repr(url))
     raise
 
   else:
@@ -450,7 +450,7 @@ def _check_downloaded_length(total_downloaded, required_length,
     # What we downloaded is not equal to the required length, but did we ask
     # for strict checking of required length?
     if STRICT_REQUIRED_LENGTH:
-      logger.error('Downloaded ' + str(total_downloaded) + ' bytes, but'
+      logger.info('Downloaded ' + str(total_downloaded) + ' bytes, but'
         ' expected ' + str(required_length) + ' bytes. There is a difference'
         ' of ' + str(difference_in_bytes) + ' bytes.')