Cassia and Grace are the only two I own at the moment. I gave my mother my Jade one, because I found Humid looked exactly the same on me, so I didn't need both.
Grace I've had for damn-near a decade. It's still good, too! Looks and applies just the same as it did when I first got it. Cassia's newer (past couple of years).
I need more Stila e/s, tbh. It's just that I keep clamoring to buy LE shit from MAC, so in the end I don't have any left for the Stila e/s I want. Ugh, stupid MAC always coming out with stupid LE collections that I feel I have to rush to buy. ~_~