Ensure the driver's phone has signal along the driving route; if not, definitely rent a GPS.

The service was okay, but since it was my first time driving in the USA and I was unfamiliar with gas prices and how to refuel in the US, I didn’t choose to return the car with a full tank. From San Francisco Airport to St. Louis Airport is less than 400 kilometers, and according to the car type provided, we only used about 70% of a tank, but the rental company charged us $57.52 for fuel. At that time, this amount could fill more than two tanks. I raised this issue with the car rental customer service, but they said they couldn't handle it. In fact, it’s very easy to return the car with a full tank at U.S. airports. This is a reminder to other customers to avoid unfair charges.