That’s right. Your hair will adjust to your hair washing schedule. The longer you can leave it between washes, the less it will need washing. It’s not just the shampoo and conditioner that you should consider if you want to increase the number of days between washes. The brush you use you make a big difference. Natural boar bristle brushes help distribute the oil from the scalp to the ends of the hair where it’s needed most and stops that greasy, limp look that comes with unwashed hair.