Check if your makeup has an expiration date stamped on the container. If there is no date, follow the general industry guidelines below. And of course if your makeup changes color at all or takes on a different odor, replace it immediately.
Liquid 6-12 months
Powders 12-24 months
Eyeliner & Eye Shadow
Liquid & Gel Eyeliner 3-8 months
Creme Eye Shadow 6-12 months
Eyeliner Pencil 12-24 months
Powder Eye Shadow 12-24 months
Lipstick & Lip Gloss
Sources: Good Housekeeping, Popsugar
Paraben-free (preservative-free) products have the shorter shelf-life.