Should you listen to the back of a shampoo bottle that says to wash your hair everyday?

Actually, you should pay attention to your hair. If your hair is dry or feels "squeaky" after daily shampooing, then you could switch to every other day. It depends on your hair. It also depends on your ethnic group. While you would likely do better with products geared to your hair type and culture, you could likely use other products if you don't overdo them. You might get by with once or twice a week. It just depends on your hair.