Why? Because you can run the risk of infection due to bacteria build up in your cosmetics. Drier cosmetics such as blush, eye shadows and powder will last longer. However, cosmetics such as lipsticks, lipgloss and liquid foundations have a far shorter shelf life.
Nail polish – can last up to one year. After nine months, you may notice color separation and thickening as the polish begins to dry. Try storing it in your refrigerator and it will last longer.