Cheat Sheet: Exactly When You Need to Replace Your Makeup

Like mascara, liquid and gel eyeliners can get a lot of bacteria mixed into their formulas through their mode of use, which means you should toss them sooner rather than later. There's also the practical side to it: even with careful storage, it's tough to find a liquid liner that'll keep from drying out longer than the prerequisite three months.

Image via @stilacosmetics