If you can’t find the label or you have more questions about expiration, it’s best to contact the company for answers. They’ll be able to guide you on the nuances of their own formulas. However, there are some general guidelines for makeup life span, and it varies from lipstick to foundation to powder and beyond. Here’s a quick crash course (with help from some experts) to help you get an idea. However, if you notice the formula starting to apply in an unusual manner (pilling, clumping, drying out, etc.), you’ll want to toss it regardless. This is especially important for liquid foundations: “Foundations are water-based and therefore are a more favorable environment for bacteria to grow,” board-certified dermatologist and YouTube creator Andrea Suarez, M.D., FAAD, tells mbg. Typically concealer is packaged with a wand that goes from the tube, touches skin, then goes back into the tube. Over time this can cause contamination (from bacteria or buildup on the skin), so tossing your concealer after it expires is even more important given that factor. “The easiest way to tell if your mascara is contaminated or is too old is to give it a sniff,” makeup artist Jenny Patinkin once told mbg. “If it smells sour or a little acidic, then toss it right away.” However, Patinkin notes you may have some wiggle room with lipsticks: “Often because they are made with preservatives that keep them from oxidizing or hardening,” she notes. “A couple of years is fine to hang on to a lipstick.” “[People want to avoid preservatives,] but in modern conventions, products are shelf stable for over a year. And keeping something shelf stable for years, especially natural ingredients and botanicals, is actually not natural,” says cosmetic chemist Javon Ford. “So what people have to understand is to have a preservative-free product, that means it essentially becomes perishable, that you have to refrigerate, use up within two weeks, and at that point it just becomes food.” The good news is that there are a plethora of less irritating and problematic preservatives out there. These tend to include preservatives and co-preservative systems to bolster their powers—and can include things like benzyl alcohol, salicylic acid, sorbic acid, benzyl alcohol, dehydroacetic acid, sodium benzoate, and more. Some of these preservative systems are even ECO-CERTIFIED. But please just know: When you see preservatives on your INCI list, it’s a good thing.