It’s time to check the car again when the renter returns. Walk around the car with the renter as you did before handing over the keys. Check for damage (maybe use a flashlight at night) and signs of possible misbehavior. Also check the fuel level and the mileage. Make sure you note all these things during check-out of the car. In case of a damage you also mention this during check-out, at the end the damage will be sent to our insurer immediately.