I have a "no heels over 2 1/2"" rule, and also say no to slides and mules as a matter of course. As far as things I still have in my wardrobe that I won't buy more of - hmm. There are some colors I have realized aren't as good on me, but the garment itself is so useful that I still wear it in combination with other colors but probably won't replace it.

I think I have larger phases about this sort of thing, too - for a few years there I got rid of every blue garment in my closet, barring denim jeans, because I'd decided that it didn't suit me. Now I've been picking up a few blue pieces, partially because I've changed my haircolor slightly, but now I know what blues suit me and which don't.