Though there are general guidelines for when you should be tossing out your makeup, it can be hard to keep track of all 80 bajillion bottles and tubes scattered about your vanity. For a more specific (and easier) way to know when your face cream is past its prime, all you have to do is take a closer look at the label. (Truth: We only just discovered this ourselves.)
What you do: Flip the bottle or tube to either its bottom or side. You should see a little jar symbol with a number and the letter “M" (month) next to it. This is the P.A.O., or Period After Opening date, which tells you how long you can use the product once it’s been opened.
Why it matters: As soon as you open a product, it starts to oxidize, and it’s also increasingly exposed to bacteria. So maybe hold off on cracking the lid until you’re actually ready to use the stuff—and not just trying to catch a whiff or peek inside. Another tip: Mark the open date on the lid so you always have a point of reference. Because, again, 80 bajillion bottles and tubes.