I didn't wash my hair for four years and it was fine- used hot water, and also rye flour + boar brush. nowadays I use a very mild shampoo about once every 1-3 weeks and use rye flour for volume
Women talking about their hair sounds like straight witchcraft, every time.
"Oh, I only wash mine under the new moon, with four bristles of wolfsbane burning nearby. In the smoke I use water boiled over yew logs grown from grave earth, and a little goat's blood. For volume."