There is a way to set the expiration date for incoming email in Outlook:
-In the message ribbon, click on the down arrow in the lower right-hand corner.
-Under Delivery Options, there is an "Expires After" check box.
-To see the expiration date from your inbox view, choose "Expires" from the Field Chooser (Found in Date/Time fields). You can get to the Field Chooser by right clicking along the headings at the top of your inbox