How to set up mac mail to keep mail on server for 1 year

Question

Hello;
i use mac mail and want to keep the mail on the mail server longer than 1 month, i would liketo keep it for 1 year.
Is there something i can configure this, instead of the options 1 day, 1 week, 1 month? 1 month is too short.
Keeping it forever is also not good.
An alternative would be to keep it 'forever' and then use the 'webmail' interface to remove mails older than 1 year
but his is too much work.
best regards

Answer 1

POP accounts will only give you control to server settings at the inbox. If you never remove it from the server, it will download all messages when you log into your account from another computer. This could be a problem with thousands of messages left on a server.
For IMAP, your inbox will atuomatically sync to the IMAP inbox, so what you do in Mail or Webmail will reflect the change at the other.
For the other mailboxes, storing messages on the server in Mail settings basically syncs the IMAP and local mailboxes like the inbox does. So, if you trash a sent message in Mail, it will trash it at the IMAP site.
If they are left in those mailboxes, then the server setting in Mail will control how long the remain in those mailboxes unless you move them or delete them manually.
If not set to store on the server, the local mailbox will not sync with the IMAP. So, deleting a sent message from the local sent mailbox will not delete the sent message in the IMAP sent mailbox.
Some accounts like GMail have settings at their site that will let you further control how mail is handled.
You can make settings to archive messages automatically when deleted from the inbox or sent folder. I believe that is the default setting in GMail. That would be what you want to save all your mail.  That would keep your inbox and sent mailboxes clean. Look at your IMAP site to see what settings you can make there.
In GMail, the "all mail" is just a reflection of all messages kept and archived. You have no settings control of this mailbox on your mac in Mail. But, you can view the "all mail" under the IMAP folder in Mail.
You can still set up a smart mailbox on your mac in mail to show the messages in the "all mail" mailbox that are greater than a year old. Only those would show up in that smart mailbox and you can just select all and delete without having to visually look at all the messages in the IMAP "all mail".