I do a lot of work on my car, originally due to finance but I genuinely enjoy working mine and my wife’s car.
The problem now is that people at work ask for help with their cars because they know I know things. I’ve changed spark plugs and air filters for a few during lunch but they ask me to do things that’ll take more than 1 Hour such as changing brake pads/discs, suspension and whatnot.
Point is, how do you say, if you want my time pay me… Or just no, your car is a shitbox and I don’t wanna touch this
So if you’re willing to do the job, when they ask you say you’ll work them up a quote. Work them up a quote and give it to them. If they go for it, cool. Otherwise they realize the freebies are gone.
If you don’t want to work on it, say no in a polite manner.
Edit: As a side note I only give free labor to family and close friends, they still buy or supply parts. Your time is valuable, don’t sell yourself short.
I tell people that I’d be more than happy to send them a comprehensive youtube video so they can do it themselves but because I hate working on cars myself I’d have to charge them.
Keep it respectful with firm boundaries and people usually understand. If it’s an emergency like a no start or something dangerous I’ll usually investigate for free but for stuff like brakes, fluid changes, yeah, you gotta throw me a few bones, that’s time that I could be using for my own projects