6 months is an average and usually given as a general "rule". Optimally, 3-6 months...it also depends on how many times you use it. If you use it everyday & especially if you have sensitive eyes 3 months is most optimal.
Also try not to move the applicator in & out several times...many women do this thinking it helps mix their mascara up, but what it actually does is add more air into the mascara & this isn't "good"...you want minimal air in your mascara tube.
Whenever you get an eye infection, especially conjunctivitis (pink eye), stys, or sick to the point of needing antibiotics, always toss your mascara, liquid liners & pencil eye liners.
Never share your mascara, liquid eyeliner or eye pencils with anyone else. If someone else uses them, toss them out...even if you've only had the mascara a week. Same rule should apply with all makeup, but especially any makeup used on the eyes and secondly, any makeup used on the lips.
at 7:55 PM on Apr. 12, 2010