You'll probably think I'm gross for saying this, but I might as well just come right out: I've been using the same bottle of shampoo for more than two years.
I know this because it's the kind that's supposed to protect colored hair from fading quite so quickly, and two years ago I colored my hair purple for the second time in my life. I remember using this very same bottle in the disgusting apartment in D.C. that I shared with two girls who couldn't clean a room if their lives depended on it. It came back with me to Chicago and lived with me through two apartments and I'm still squeezing pink goop out of the bottom of it as of today.
It's not one of those gallon jugs with a squeeze pump, either. This is a regular old double-size Herbal Essences bottle, the kind you pick up on sale for like five bucks when CVS is having a special. It's just that over the past two years, I simply have not washed my hair enough to necessitate buying a replacement.