Excellent question! You want to make sure that the unit is in good condition. The last thing you'd want to figure out is that there is a huge problem AFTER you've moved all your stuff in. Use a lamp to make sure all of the electrical sockets are working correctly. You will be able to notice any problems with the floors or walls but also check areas behind doors and inside of closets. You will also want to check that the appliances are working correctly and that there is no evidence of terminates or water damage.