The humor in a bottle of shampoo

Why is it that my husband can have a bottle of shampoo last 6 months and I can't make one last longer than 10 days? Really why is that? Oh wait I know the answer...it's because I actually have hair on my head, LOL! The same goes for hair gel, his tube lasts for what seems to be an eternity and my hair stuff is lucky if it last 2 weeks. Granted his is a 6 or 8 ounce tube of hair gel and I have a 4 ounce bottle of anti frizz cream. Still it's just odd how men don't seem to go through the hair care products the way women do.