I have a lot, but chalk it up to trial and error. There are only a couple of pairs that I wear ONLY when everything else is dirty. Mostly they're "okay" and stay in the rotation. The "really good" ones I save for the long rides, but as the others wear out, they'll get replaced with more copies of my favorites. Unfortunately I don't have a "perfect," so my favorites include "great chamois but too stretchy fabric" (EO Very Short), "great chamois but too short legs" (Castelli Provocante) and "really good chamois with just-right shorts" (LG Neo Power). I could choose any of those three for a long ride, but I'd tend to gravitate away from the Castellis because of the legs being too short.