Lipsticks rarely ever go bad, but Dr. Pugliese suggests keeping them anywhere from one to two years. "If you keep a lipstick for two years, you're not using it and there's really no sense in keeping it longer than that," he says. But if you do go beyond that, you're probably safe. Lipstick are extraordinarily stable—they're anhydrous (that means, there's no water in them), so they can last a long time.