1. Is it a neutral or does it play well with neutrals?
2. Can it be worn for different occasions and in different ways?
3. Is it in perfect condition and does it fit me perfectly?
4. Do I love it?
Applying these rules made it fairly easy for me to part with a great many things. For example, this beautiful silk Madewell blouse. It meets criteria 1, 2 and 4, but alas the fit is off. I've tried denying that for several years and worn it anyway. I realize that it doesn't flatter me.