Most barbers and stylists recommend shampooing hair only once or twice a week. Why? Washing daily with any shampoo, even with the low-sulfate kind, will strip some oil and dry your hair and scalp. What's more, most styling products like gel and hairspray are water-soluble, so they don't need shampoo to rinse out of hair. Although switching to a once- or twice-weekly washing can cause your hair to look greasy at first, it won't after a few weeks, and your hair will be healthier and softer.