Just like skim milk, your over-used and abused Visa card and your gym membership, beauty products expire. Most brands have been clearly labeling their products with expiration dates right on the packaging.
Cargo stepped it up a notched with their latest lip gloss that incorporates Timestrip technology. It's a tiny strip that's embedded in the cap of the lip gloss and automatically keeps track of how long it's been open. After nine months, the window displaying the strip turns red and alerts you that it's time to toss it. Cargo blue_ray High Definition Gloss is available here for $24.
Just an FYI: You should replace your mascaras and liquid liners every three to four months and foundations every two years.