This morning I spent five minutes attacking a frying-pan with a hammer; this afternoon I spent two hours taking a bike wheel apart and putting it back together again. Repair and reuse.
The frying-pan had an increasingly large rise in the middle -- bad enough by now that you were guaranteed a patch of burnt-on stuff where the oil wouldn't sit. Not sure if the hammer solution will actually work, as I didn't get it all that flat, but it was getting to be unusable, so I can't have gone that far wrong. So that was the repair.
The bike wheel is suffering from a broken hub. I did take the hub apart to see if I could fix that, but the cup (definitely) and the bearing races (probably) are dented, so it's a bit past that stage. I did keep the bearings, though, in case they come in handy. What I figured I could do was to reuse the spokes, nipples (the bits that attach the spokes to the rim), and rim. So far, so good: took everything apart successfully, and have got the basic tensioning done. Next job is to true it properly and put the sprocket back on -- probably about another hour's work. And that was the reuse.
There's something very satisfying about fixing a broken thing, or about not wasting reusable parts. I doubt I've saved any money (when I account for my time) with the bike wheel, but the satisfaction is more than worth it even without the environmental advantages. And I trust my wheel-building over a factory wheel every time.
Plus I got to hit something with a hammer, which is always a pleasing experience.