Think spoiled milk is gross? Try a year-old mascara tube on for size. "Like food, makeup has an expiration date, and over time cosmetics can harbor harmful bacteria that can lead to infections," Dr. David Schlessinger, a board-certified oculoplastic surgeon and ophthalmologist, told Marie Claire.
The thing is, unlike milk, makeup won't give off that obvious smell that makes your senses go "whoa, put that down." In many ways, makeup is more sneaky than that because it can sit in your cabinet for months after it's gone bad with you none the wiser.
You're not completely powerless in this struggle, though. Arm yourself with the power of knowledge, and you'll be in a much stronger position to let go of your makeup when its time has come.
Foundation: "You increase the odds of bacterial growth – and, hence, of breakouts or irritation – when you repeatedly dip your brushes and fingers into liquid foundation," Good Housekeeping explains. Liquid face makeup has a lifespan of anywhere from six months to a year. A good tell-tale sign is when the ingredients begin to separate or the smell turns funky.
Powder: Good news for all you shadow junkies out there – anything in a powder form (be it pressed powder or shadow) can run you a good two years. According to Good Housekeeping, powders tend to last longer because bacteria has less of a chance to grow where there's no water.
Mascara: We'd bet about three months on any tube of mascara, but we probably won't have to tell you that. It's easy to figure out if your mascara has gone bad because it'll be dry and difficult to apply, and you'll probably toss it in the trash out of frustration well before the threat of bacteria sets in.
Lipstick: Give this one about three years – and for gloss, one. Have your doubts? Open the tube and sniff. If you don't want your pout smelling as such, it's time to say buh-bye.
Eyeliner/lipliner: If it's pencil form you're talking, two years. If it's a liquid liner, three months. The same rule applies here that we saw with powder versus liquid foundation, and pencil liners are especially hardy because you get a fresh, clean surface every time you sharpen them.
Nail polish: Most experts agree that you've got a year tops to use up your favorite bottle, but you might determine this more on a case-by-case basis by shaking it, according to Beautylish.com. If it still looks like a water/oil science experiment, toss it.