I have these bad habit of rotating my shampoos. At anyone one time, I have about five bottles of different kind of hair shampoos. I have cheap ones which I bought from hypermarkets to those that costs 10 times more than the usual shampoos.
I notice that my hair react better if I use different varieties of shampoo. They probably don't get lazy with the same time and hair look fresher.
That's why I need a huge place for my bathroom vanities to store the three types of bath soaps and five bottles of shampoos plus hair conditioner.