Basically, if it turns on or off, opens or closes you want it demonstrated and you return the demo. Check all caulking, get up on the roof and check it out. Make sure everything runs and works as it should. Videotape your pdi. Have them demo the hitching and hitching process and explain how to make adjustments to your hitch as well. Do not forget to make them show you the water heater and water pump locations as well as low point drains. Have them teach you how to winterize and dewinterize the unit as well. Do not give them any money until the pdi has been completed to your satisfaction and any repairs performed. Do not go for the old, bring it back under warranty spiel as you will lose camping time waiting. Make them work for your money.