Have a figure in mind, WRITTEN down and agreed to before even getting out your old sewing machine.
This will be a very tricky thing to do, please let us know how it turns out.
I think seriously how much I like a garment of my own before mending it. Can I replace it cheaply, do I really love it and does it fit and make me feel good? As for doing that for others just because I was dumb enough to mention sewing, I don't even start that!! The word might get around.