I'm one of those replace-and-patch-at-home types. I carry one spare and if I get another flat then I will do a roadside patch. However, I rarely get flats. OTOH, I am picky about my tubes and I'm a bit picky about paying too much for them too. I like a specific tube brand with a specific valvestem style and they're not always on sale. I pick up a couple when they are but as a result I'm encouraged to patch my old tubes and not just throw them away. I also give them away to friends. The only tubes I don't reuse are the ones which have had the valve pull out. I find other uses for that such as turning pieces of them into a plug for my seatpost in order to hold spare spokes...



... or using them to line the jaws of my homemade repair stand...