This depends on how often you clean or wash your hair. If you wash it regularly, you can use the scalp exfoliation scrub only once every few weeks. But, if you do not wash it often, or if you use too many hair care products, then there will be more scale build-ups. So, you have to use the scrubs at least once a week.  However, we suggest you not exfoliate more than twice a week as you will have irritation in the scalp.