Daily hair washing is often thought to be the key to a healthy scalp, but that's not entirely true. Oil balance Understanding scalp oil balance The scalp produces natural oils that keep hair healthy and moisturized. Water quality Impact of water quality The quality of water used for washing hair also plays an important role in scalp health. Product impact Role of hair products The kind of products you use also determines how often you should wash your hair. Diet & hydration Importance of diet and hydration Diet and hydration are also key to a healthy scalp.