What elle said...
--especially for tops, where there are so many different proportions for different bottoms, for roomy vs. fitted, boxy, etc, I will hold on to several tops that fit well in shoulders, nice fabric/color or basically I like it, that might be "short" for what I have now, but would be perfect with a pencil skirt I might one day get, or "long," but if pant waists fall, l then will be back to longer tops. Or is very slightly oversized but doesn't swallow me, then I recognize that may trend in and out. That sort of thing. Usually but not always it's a knit, maybe even cashmere or merino, in a good color and good condition that will make an instant outfit with the right bottoms and is aligned with the types of things I would wear more or less of depending on availability and style trends.
Shoes are similar and a problem if my goal is to keep fewer, well-used items--if shoe has a very good fit and comfort but seems off-trend, I will keep it (I have room, but don't like the idea of the shoe mortuary). That is due to my experience that I can never just run out and find the right shoe when I need it--I am so envious of people who can just buy dresses or pants or whatever and pair up beautiful, stylish shoes immediately. However, I try to review them at least annually--shoes can actually deteriorate and flake, or the fit may have changed, and then tossing is simple.