Background
When Exchange 2010 was implemented in the fall of 2010 at Tufts, as an implementation team we agreed to forgo the auto-removal of messages placed into the trash as a way to make the transition from then Trumpeter-Mail to Exchange easier for faculty, staff, and students.
How it works
This is a standard 30-day retention setting that can be applied on a per mailbox basis. Once configured, exchange automatically removes a message placed in the trash bin from a mailbox 30 days after it is moved to the trash bin. This setting does not care when a message was sent or received, it only matters when a message is moved to the deleted items folder. This retention policy only takes place in the deleted items system folder (trash bin) in the mailbox.
Items that have been purged from the Deleted Items folder can be recovered within 60 days using the Recoverable Items folder.
Implementation & Scalability
This configuration has been applied to all students mailboxes on a per-database basis. We will continue to roll-out the policy on a per-mailbox basis to staff then faculty this summer. Starting July 1, all new mailboxes will be configured with this policy.