I tend to follow what I call the "toolbox rule," mostly because I've used it the most with tools. If I find I need something, I'll buy a cheap version of it, even if the cheap version is noticeably lower quality (which it almost always is). Then, if I use said cheap version enough that it either breaks or is no longer useful to me anymore, I'll buy a nicer one. It helps me justify the greater expense and demonstrates the need for it.
I've done this with umbrellas, camelbaks, tents, ski equipment, but mostly, as stated before, tools.