Someone did an experiment where they asked women not to wash their hair for a month, and after they washed it was the softest it had ever been for those women. Hair products and over-washing can be very damaging for your hair. I have lots of very fine hairs, that are somewhat wavy, if I use the right products it is very easy to take care of... otherwise it gets knotted and greasy. I wash my hair every other day, if I do it every day it starts to get coarse and greasy. But by the third day it gets gross. If I'm in a rush I have dusting product that absorbs the grease and smells like Candy, but I never go more than 3 days without washing it.
You also gotta pay attention to the pH of the products (I'm not sure if high or low is bad). Pantine Pro V & Herbal Essences are very bad for your hair, and end up forcing you use other products like moose & gels to make it soft again. I had a friend whose hair started to thin & fall out after using Pantine Pro V.
My hair dresser could tell that I was using Herbal Essences for awhile because my hair was more knotted and harder to cut. At first it was very soft, but it got knotted a lot easier.
Long hair is hard to maintain sometimes & often people need to play around and figure out which products work for them. I have finally settled on a shampoo in the last year or so that actually works for my hair, but it took a long time to find that.
Don't judge a woman based on how often you think she should be washing it... hair can be very finicky and we sometimes have to work very hard to figure out how to make it naturally soft and beautiful. When it comes to curly hair it's an entirely new game... my moms hair is it's softest and nicest 3 days after being washed & I think she washes it twice a week.
Boys, we work hard to make ourselves pretty for you, you don't really need to know how we do it... it might kill the magic. My boyfriend always tells me how soft my hair is and loves touching/smelling it... when I first told him that I only wash it every other day it kinda surprised him and I had to explain the long complicated details of how I take care of my hair. But he still loves it & because I take good care of it I've managed to grow it out pretty long.