Hi @jaydee , this topic has been discussed a lot on the forum. For example:
https://forum.trustedhousesitters.com/t/cars-for-sitters/
In the US, car insurance follows the car, so if you have liability and collision coverage, it will cover a driver who has your permission to drive your car. Here is some useful information from Allstate Insurance:
https://www.allstate.com/resources/car-insurance/my-friend-wrecked-my-car#:~:text=Most%20car%20insurance%20policies%20will,permission%20to%20drive%20your%20vehicle.
At present, I am at a sit and am driving the owner’s car. If I were to damage the car (knock wood, spit three times), I would pay the owner’s deductible. This is not documented , it’s just understood. I had the owner fill out my own Authorization to Drive a Motor Vehicle, a form I modified from a template I found online. It includes my name, address, phone number, driver’s license number, my own auto insurance policy number, the owner’s name and signature and the dates I am permitted to drive the car. I keep the completed form in the glove box. This should provide coverage in the event of any type of mishap.