If the vehicle is given to the driver with a full tank of gas, the tank must also be full upon return. The vehicle should be kept clean and returned clean—no exceptions. The renter is subject to fees if these terms are not met.
The renter is also responsible for alerting the vehicle owner if there is a problem with the vehicle. For example, if the vehicle is due for an oil change based on the sticker that should be on the dash, the renter must notify the owner. The owner is then responsible for scheduling the service.