Deleting emails from a sender after x days?

Solution 1:

I accomplished this by creating a new rule that automatically moved all emails from a specific sender into a folder.

This folder then had AutoArchive (Right click folder, Properties) set up to permanently delete items older than x days.

Solution 2:

Using the outlook scheduler you can add a task to delete all emails from folders older than a certain amount of time. Also in the same rule you can empty the trash of all items older than a certain amount of time. Automate when it runs and you have solved your problem. On my mac the scheduler lives under the tools menu.