there is a log in the sql databse 

What is the table called?

i think it is ow_mailbox_messgaes 

How long does it keep messages for?

i dont think the table gets cleared 

James, they will storage till the Messages plugin deinstallation.  Or if you need, you may delete them manually.

So Taissa.....I think oxwal needs to create a cleaning button in the message plugin to be able to delete old messages from the database automatically (say like anything over 90 days) don't you think? Be a LOT easier on everyone...just my thought! 

Wilson

before post reply...lol....heading over there now...lol >> http://oxwall.uservoice.com/...lete-old-messages-fr

Hell of a lot easier

Wilson, I think it is a good suggestion and hope many will vote for it. But don't forget, that not so many users are need of this feature because not so many faced with the issue that  ow_mailbox_messgaes table is too big.