The Recent Items feature resides on the Autotask main navigation menu and expands to show by default a listing of the last 20 items you have accessed. 

Instead of reentering search commands, use this listing to go back to accounts, opportunities, tickets, projects, purchase orders, etc. When you select the View More command a More Recent Items window opens with a listing of the last 50 items you have accessed.

The menu also offers a Clear option to remove the history of all items.