Some eyeshadows - especially the older/drier formulation eyeshadows last for years. I've had MAC eyeshadows and old NARS eyeshadows and Viseart shadows last well beyond 2 years with no noticeable change in quality . However I find that the newer creamier softer press eyeshadows do decline in quality over time. For example my ABH modern renaissance is now about 2 years old. The eyeshadows are less creamy and now are a drier and even more prone to kick back/fall out. They are still usable with a bit more care but I can tell that their shelf life is limited. I'll probably destash that palette in the new year. For reference: my eyeshadows are stored in a cabinet in my makeup room with controlled temperature/humidity.