Have you ever wondered about all of those little palettes of color and if they are really too old to be useable any longer? It hurts to throw away makeup that hasn't been used up, but for safety's sake, you should give it a little thought.
According to the FDA:
"Cosmetic products are generally formulated and tested for a shelf life of 1- 3 years under normal storage conditions, depending on a product's composition, packaging, preservation, and other factors. Consumers should be aware that expiration dates are simply "rules of thumb," and that a product's safety may expire long before the expiration date if the product has not been properly stored.
Cosmetics that have been improperly stored, for example exposed to high temperatures or sunlight or opened and examined by consumers prior to final sale, may deteriorate substantially before the expiration date. On the other hand, products stored under ideal conditions may be acceptable long after the expiration date has been reached."
Even properly stored, contaminants will get "into" the product... especially eye makeup. Think about what you are using to dip into the product each time...
So a good a rule of thumb of how long makeup can be stored:
Lipstick: 1 year
Eye Makeup : 3 months
Blush: 6 months
Nail Polish: 2 years if stored properly