Duplicity should not run with --extra-clean by default
Running duplicity with the --extra-clean option removes the signature files of every backup chain but the latest one. This means that duplicity itself can't work with the older backup chains any more. The problem is the same as explained here: http://stackoverflow.com/questions/11543307/duplicity-file-to-restore-only-uses-newest-full-backup. I am right now stitching together an old backup by hand, which is quite a pita. Just because an option is available, doesn't mean that it's a good idea to use it. Please make it configurable or remove it altogether and let people who have little backup space enter it in the generic options field. The way it is now, it is a major annoyance for people that rely on their backups being easily accessible at any point back in time.
(from redmine: created on 2013-10-10)