Check out Femalenetworks' post..
According to the website, here's the lifespan of some makeup items:
1. Lipstick: one to two years
2. Foundation: one year
3. Eyeliner: six to 12 months. It can last longer but make sure the tip is sharpened and clean before you use it.
4. Eye shadow: six to 12 months
5. Mascara: three months. It easily breeds bacteria.