Your activity level and interests. Do you play sports or spend a lot of time at the beach? These kinds of things can affect your hair. For example, if you're an athlete with oily hair, you may want to wash your hair after working up a sweat during practice and games. But if you're a lifeguard or a swimmer, sun and saltwater (or the chlorine in pool water) can dry your hair out, no matter what your hair type. If you're exposed to sun, wind, or other elements, you may want to use a shampoo designed for dry hair or use a conditioner. It's also a good idea to wear a hat to protect your hair when you're outdoors.