Shampoo is expensive – we tend to use twice as much as we need to. Because we apply it to one spot on the crown of the head, the hair there can become damaged and break. I now spread a surprisingly small amount of shampoo between the palms of my hands, then apply to the sides of the head first, then to the back and top. Of course it depends on the type and length of your hair, but I use less that a 10c coin size. I also find that by not leaving it on for a prolonged period I seldom need to apply conditioner, and my hair has never looked better, so it’s a win-win.