Sewing with a thread and needle is a serious skill. I had no idea how complicated it is, so when I decided to repair my wallet, I figured it would only take a couple of minutes. I am very glad I decided to repair the wallet so I could learn how difficult it is while in the comfort of a hostel, and not while it is raining and cold and dark.
I broke two needles. I broke some flimsy little thing that I think is used to help thread needles. I have holes in my fingers–not from pin pricks–but from trying push the needle through the leather. I bent three sewing pins and I learned how useful they are. I learned some things about knots, especially that I do not need one on the needle. The repair is unremarkable and it took two hours, but I think these two hours saved me many hours of frustration when I need to do a more serious repair under more difficult conditions.
There are many skills I have yet to learn.