Tossing Out The Old Mascara: Do you follow the 3-month rule?

Mascaras, once opened, have to be replaced after about 3 months - that's the makeup rule.  I don't use makeup that often, about 2 times a week at most, so I find it a little difficult to part with an almost brand new mascara just because it's 3 months old.

Old Mascara Discard 3 months makeup shelf life

I got my Covergirl Natureluxe mascara some time in August, and it's November now, so I guess I should be switching to a new tube now - but I was just wondering, does everyone follow the 3-month rule or do you think it's okay to stretch it a bit?