If you do this often you may want to invest a few extra buks and replace the locks with the kwicset smart key. They run about $10 bucks more but all the locks can be keyed to 1 key for each rental and the lock dont have to come off the door to re-key. Just hold on to the keys from differant rents to change the locks when you want. Anyone can change the lock in seconds with the tool they sell with the lock, and the working key to the lock. Insert old key and turn to change pos. insert tool and remove key. Insert new key and turn back. your done.