Please fill in this template when reporting a bug, unless you know 
what you are doing.
Description of Problem:

I'm new to Evolution. I tried looking around in the bug list but could 
not find anything similar to this, so.... 

For people who pick up their e-mail from a remote POP3 or IMAP server, 
it's helpful to have a functionality that allows Evolution to 
automatically delete e-mail from the server after they've been in the 
an arbitrary number of days. 

The typical scenario in which this is useful is that of somebody 
retrieving e-mail from both home and work--you can't set either 
instance of Evolution to automatically delete messages because the 
other program may not have picked them up yet. As a result, the 
mailbox keeps getting bigger, up to the point where the popper takes 
several minutes just to return the list of messages in it.

Being able to set Evolution to delete messages after a certain number 
of days creates a buffer that allows both programs to pick up the 
message, while keeping the mailbox down to a reasonable size.