Cosmetics are pretty easy to organize – first decide how much space you have. Do you have a whole vanity, a dresser, or simply one shelf in the bathroom to keep your makeup? A vanity or dresser drawer can be compartmentalized by buying trays with different sections in them, which are available from stores like The Container Store or Bed Bath and Beyond. In each different section, keep all your lipsticks and balms, eye shadows, blush, foundation bottles and compacts. Get a short mug or a stubby clear glass, and in this, keep lip pencils, eye pencils, mascaras and lip gloss tubes. 

 If all you use is mascara and lipstick, ever, you can afford to keep it all in a tiny yet sassy makeup bag like this one, from Le Sport Sac: 

As you organize, take inventory by dumping out your all your makeup into one pile and sorting the contents. Anything that smells funny or has changed color or dried out goes in the trash. If you've lost the top to a lipstick, slice off the color and put it in an empty pillbox (add a deeper color or a dab of gloss, and you can make your very own personalized lip palette that goes from day to night). Use a zippered case or sandwich-size Ziploc bag to hold eye and lip pencils that are missing covers. Throw away cracked powder blush because it's very hard to use and might spill. Make sure all the colors you have are right for you, and if there’s something you haven’t used in a year, throw it away because you’re never going to use it!

 Mascara: 3 to 5 months 
Cream blush or cream eyeshadows: 6 months to 1 year 
Concealer and liquid foundations: 1 year
Eye pencils, powder eye shadow, under-eye cream: 1 year 
Foundation, lipsticks, facial moisturizer: 1 to 1½ years 
Face powder, powder blush: 2 years