Eye liner pencil - 1year..this can last longer because you can sharper it and it does not become a breeding ground for bacteria.
Mascara - 3-6 months...YIKES!!! The reason being is that we tend of pump our mascara to get more on the wand and that lets air in which dries it up AND lets bacteria in.
Blush, Eye Shadow and other "powder" products - 1-2 years. However if you notice an odd smell or the color changes significantly, then it is time to toss!!!
Foundation - 6 months for the "pot" style and 1-2 year for the "pump" style. But keep in mind that it is wise to change out your foundation if you do have it for a year or two. Your skin will get use to the formula and it will be time to try something new!!
Lipstick - 2 years. But if you notice a smell or color change it is time to toss. Also, it is smart to clean and wipe them off from time to time and spray them with a little bit of alcohol.
Make Up Brushes - Should be cleaned 1X per month. Here is the best way to clean your brushes according to Elle magazine: