Hairday Hygrometer

I heard on Australian radio once that women spend more money on their hair than men spend on their cars. So this idea is really a marketing gimmick, although slightly sciencey.

It is my considerably uninformed opinion that hair reacts differently to different levels of humidity, etc., etc., and that some shampoos may attempt to redress this. The idea is to include a hygrometer with your shampoo packaging, with which women and hairy men can match daily humidity levels to a range of shampoos which are numbered by humidity range.

I have very little idea whether this is how hair meeks out its daily existence. Regularly having more hair than I want or need, I don't even own a comb, never mind a hygrometer.