I think shampoo is important.

I used to use cheap shampoos thinking there wouldn't be much difference since I was just going to wash my hair, but I switched to an herbal shampoo and it is definitely better. My hair is extremely curly, so I used to have to get a straightening treatment every six months, but after switching to this herbal shampoo, my hair quality improved so much that I haven't had to get it done for two years. I didn't think shampoo was important, but it seems it really is.