Aug. 24, 2009 -- Question: How often should I change my eye makeup?
Answer: Changing your eye makeup often is crucial to avoiding eye infections. The rule of thumb is typically to change your mascara and your eye liner every four to six months. Eye shadow can actually last a little bit longer, almost to about a year. But if at any point in time you develop an eye infection like conjunctivitis or pink eye, you should immediately throw away any makeup that has come in contact with your eyes and just start fresh with new products.