When you need to throw out your makeup
Mascara - get rid of it after about 3 months. You should only keep it only for a short time because it can become a breeding ground for bacteria. It also dries out and becomes clumpy on the lashes.
Foundation - keep it for a year unless it changes colour or consistency. You can keep concealers for up to 18 months. Anything you apply with your fingers has a shorter life span because your fingers carry bacteria, so think about finding a foundation in a pump bottle.
Powders - these include blushes, bronzers and eye shadows. You can hang on to these for about 2 years. For cream blushes and eye shadows, say goodbye after 18 months.
Lipsticks - they tend to last a year but lip glosses last up to 2 years, unless they get a little gooey.
Eyeliner - if you use a pencil you can keep using it for 2 years unless you get sore eyes or conjunctivitis. Then you should throw out all eyeliners and your mascara. Gel and liquid eyeliners last about 3 months.
Always remember to clean your makeup brushes every 2 weeks. It extends the life of many of your products.
Main pic: accelrys.com