1) Basic stitching is so ridiculously simple that even I know how to do it, you can learn it in like 5 minutes. I sewed up a hole in my old jeans the other day and I'm fairly sure the part I fixed is stronger than, and will last longer than, the rest of the denim.
2) In my experience unless it's quite expensive (to the point that you wouldn't want to have to replace it) then you can machine wash pretty much anything, even if it says dry clean only, just use a coolish wash.
3) I just put most things in together (excluding suits). Nothing has shrunk or changed colour so far so I'm sticking with it.
4) Learn the power of compound interest, start as young as possible even if it's only a small amount.
1) I can't get things to look as nice as I like to. It's always 100% obvious I tried to patch the holes.
2-4) Thank you! I'm gonna look into the compound interest thing.