DisSent (short for "Distribute Sent Mails") is a
program for separating your sent mail from a
single folder into different folders based on
properties of the individual messages in the
folder. It scans your mail storage and proposes a
set of actions to tidy up your sent mail folders.
More precisely, it gives you a list of messages
along with proposals on where to move these
messages. You can then select the messages you
want to move and let DisSent do the actual work.