Okay, so a while ago I switched to using multiple IMAP mailboxes to help me organise the chaos that is my e-mail. In addition, I have my Dreamhost Mail settings set to delete read messages after 45 days, or if they exceed 500 messages, as I also have an archive mailbox stored locally on my computer to retain e-mails I want to keep (which is then backed up).
However, in my custom mailboxes I'm still seeing messages going back to the beginning of May (when I configured most of my new mailboxes), which suggests that my messages aren't being deleted automatically at all from those mailboxes.
Are these automatic deletion settings only applicable to the main inbox? If so, is there a way that I can expand the behaviour to affect all my mailboxes? Like I say, I have my own archiving system, so I'd like to keep my incoming mailboxes as lean as possible.
I'm using OS X's Mail on Mountain Lion, and it doesn't have any options for deleting old mail from other mailboxes, only for deleting mail from the Junk, Sent and Trash folders.