emails won't delete

[charlie]

hey all. I'm curious. I've got kmail/kontact set to delete my emails after a
set number of days and neither one will do that. I create a POP3 account with
all of the credentials and I've still got email on here from a couple days
ago. What do I need to do to alleviate this issue? Thunderbird does this
really well and I want kmail to do the same thing. Should I create an IMAP
email account to handle this feature better?