Why I don’t let others drive my race car

There is only one friend that I will loan tools to or borrow from, known each other for almost our entire lives. I know that I can trust him and vice versa. I have had his parts washer for a couple of years now, mostly because he has no room for it, he has borrowed my engine crane, and some of my power tools. We have a key for each other's garages so there's never been any problem.