I don't usually repair thing for others. One of my son's friends just got a job and I am hemming 5 pairs of work pants for him. They are really easy and I don't mind helping him since he just started working again.
A friend at my sewing group asked everyone if anyone could fix her husband's silk tie he had purchased in Hong Kong when he was on a business trip. No one volunteered but I did. It was fun like working a puzzle. It had to be done by hand. She did it as a surprise for her husband and he was thrilled to have his favorite tie back!
I have a friend who has a "cat" quilt which is coming apart and she asked me if it could be fixed (hinting for me to repair it), I told her the material was too old and it would be a lot of work but I told her I would loan her a machine and she could work on it. I was not going to waste my time and get tangled up with that mess that cats wallow all over.
I just am selective but rarely do any sewing for others… mostly just immediate family members...