I put myself thru college making Prom or bridesmaid dresses, I found out (the hard way) that people will pay for these fancy dresses, but if they want a simple sun dress, they don't want to pay for your time.
I will only replace zippers for my girls, I won't touch men's pants. I will only hem or alter for the girls. People find out that you sew and they expect you to do it for free or a couple of bucks. One time someone from work asked me to "finish" a prom dress her daughter had started. She just cut it out, and the dance was a few days away. No way!!