I have no idea. I know I have some that I wore once in college 10 years ago when I weighted 50 lbs less than I do now (I weighted too little and wasn't healthy then, I weight too much now).
I need to just dump the entire drawer on the floor and sort through it. My stuff that is in heave rotation (like cotton that I wear running) is losing elastic strings. At least this gives me a better non hoarding benchmark.