Ever get sick of being the family and neighborhood mechanic?

I am just about sick of it. I work 6-7 days a week as it is and don't really need the extra money. My wife thinks that is no big deal to help them out. Not too long ago I spent all day changing my brother-in-laws timing belt on his Toyota truck. He just watched and when I was done he just said thanks for your help and drove off. I don't think that he realizes that is at least a $500-$600 job. They are great people and that is the only reason why I do it. I don't mind answering questions or pointing them in the right direction, but I need to draw the line somewhere.
I have turned some of them away. "If I buy a truck that isn't running can you get it running for me"? No! I guess that is why now they are resorting to just dropping them off in my driveway.