I have camped and backpacked all my life. My hair is straight and baby fine. That is great for drying quickly, but it also gets yucky quickly too. So I almost always do at least a spit bath and a hair wash daily. Sometimes it was in glacier water that was cold enough to give you an instant headache. Now that I am older I enjoy a few more comforts camping.
I still wash my hair daily, but I at least wait now to heat the water and usually shower at the same time. (I have a 6x12 cargo trailer) I still only boondock camp so I bring my own shower. Having a battery and solar recharger brings some added benefits above backpacking too. I don't blow my hair dry, but I do use a 12v Roadpro curling iron to manage it and get it back out of my face. It heats up quickly and works well. http://www.amazon.com/gp/product/B001JT ... UTF8&psc=1
Most of the day I am still wearing a buff (sun protection face mask) and hat, so kind of crazy.