I never do work on anyone's bike. I have friends or coworkers that ask and I decline. There is liability attached. LBS is insured and probably has certain waivers, if you do work and something fails leading to serious injury or worse you could end up getting sued. I enjoy working on bikes but I have trouble finding time to fit in my own projects sometimes between work and family so I'm not going waste my valuable time working on someone else's bike for a couple of bucks