This may be obvious, but if your product's expiration date is past, then toss your product. Some products, usually those made with clean/green ingredients or less powerful preservatives, will note the exact date. Many others have a little jar symbol with a number next to it that indicates how many months it'll last once opened.
When in doubt, refer to the visual warning signs we outlined in the previous slides. Worst case? You have a great reason to buy something new for yourself!
Image via Imaxtree