It is recommended that you do not wash your hair every day. Washing your hair too much can cause the hair to strip and become brittle. At the most, you should wash your hair every other day. You can gauge how often to wash your hair based on itchiness or if it becomes visibly oily. If you are an active person, you can still skip the shampoo and rinse your hair with water and conditioner. How often you have to wash your hair depends on your hair type as well. Those with fine, straight hair are going to have to wash with shampoo more frequently since it will become oily more quickly.