[Update: I added some further comments on this here.]
Use it up, wear it out...
There's some debate there about what "wear it out" means. Does wearing something out mean to keep fixing something until there's no place left to patch? Or wear it out as-is, like driving a car full of rust holes and belching smoke out the end? How far do you take this before you give in and replace something that's unsafe, inefficient or just ugly?
I don't think there's one right answer. I do think that "wear it out" includes refinishing, repainting, patching, darning, and replacing parts if you can; it can also just mean squeezing the last out of something. But there's a difference between wearing a sock with a hole in the toe and re-using a worn out baby car seat or a lamp that short-circuits.
Which brings us back to one of Mama Squirrel's favourite rants: how come socks don't last as long as they used to? How come the stroller we bought for Crayons was toast after just one kid (even though it was treated nicely and not dragged through the snow the way The Apprentice's old beast was)? How come the Barbie heads crack off and the new sheets shrink beyond recognition? How come more things aren't user-repairable?
Of course I know why. They're mostly made overseas, as cheaply as possible. The plastic parts snap off at a touch. We're supposed to buy new things, not fix the old ones. Besides, most of us can't be trusted to know how to open the back of something. Or someone thinks we just can't be bothered.
You could say that the joke of "wearing it out" is that most things these days "wear out" without any help, one week past the warranty period. Our stove is on its fourth oven element, and that's not a tribute to our resourcefulness, it's a rant against poor workmanship. (The first time one of the elements broke, it shot sparks out the oven door, made a hole like a cigarette burn in the kitchen floor, and scared me half to death. Since then I keep an eye on the element, and if I ever see any funny red bulges while it's heating up, I know it's time to replace it.)
The challenge now of hanging onto something long enough to wear it out is finding something that's worth wearing out in the first place.