WHAT DO COSMETIC EXPIRATION DATES MEAN?

In general, liquids and creams expire fastest, while powders tend to last much longer. The more wet a product is (take mascara or liquid eyeliner, for example), the easier it will facilitate bacteria growth. There's moisture near your eye so you may be introducing small amounts into the tube. Pro tip: Dry and over-clumped mascara is past its prime. Toss it out Now!

Be sure to ditch your eyeliner when the wax becomes way too hard, besides it will no longer glide evenly.

Your eye shadows, on the other hand, can stick around for quite a while.

Pro Tip: Be Sure to Use Clean Applicators to Reduce the Chance of Microbes