Black hair is drier than other hair types, so it needs to be washed less often. According to the American Academy of Dermatology, black hair should be washed no more than once every 7 to 10 days. This interval is good for balancing natural oils and removing excess buildup.  However, some hair types need more frequent washing. The time gap between washes also depends on individual preference and the products used. It is best to wash your hair after every 5 days to keep it clean and prevent damage.