After wearing them only three times they got a hole in both heels. Not good. I guess this is proof that if you're going to make and wear hand knit socks in shoes you really need to make sure there's some nylon or equivalent in the yarn, although I didn't think it would be quite so quick. Maybe my shoes have extra friction heels or something?
I make a point of not mending socks. A certain person I know manages to go through socks at a tremendous rate, and if I said I was going to darn his socks that's probably all I would ever do! So no, I don't mend socks. Apart from if they're hand knit and have only been warn three times!
That said, I do have an inherited darning mushroom which I put to good use. I didn't use darning wool, but decided to use normal sock yarn with nylon in it. I've seen prettier, but hopefully that'll work.