It's a luxury, but also a lot of waste. Did you know that every product that you got in your bathroom got an expiration date? Well, they do. The products you got last from two months till three years (mascaras to perfumes). So every now and then you should clean out some make-up. Not only becuase there's always new trends to follow, but also to save your skin from irritation and rashes. You should also wash all they make-up brushes you use every week. Just use some mild soap or shampo. You can feel how soft and clean they get, and how easy they are to use when they're fresh. It also helps your skin to avoid more zits (sweets and other unhealty food can do that by themselves).
Anyway, I'm gonna go and get rid of some make-up products. I only use one eyeshadow anyway, a color called "Khaki" from IsaDora. I got a few other palettes I like to use when I wanna try something else, but I don't need fifthy different colors! And all the lipglosses that doesn't do anything else than give a shiny lip and no color, no matter how flashy the product looks on the outside? Well, I need color! And all the summer nailpolishes that won't see the light until next year? I'll put them away for now.
Make-up is just the same as clothes - seasons change, trends and it-colors change, so go clean! You feel so much better when you know that you only got your favorite products laying around, and maybe you get some new inspiration?
Good luck!