The more often you shampoo your hair, the dryer it will become. Your hair should be shampooed every three days at most. Your hair can not naturally produce it's own oils if it is constantly stripped of them. Start the process of training your hair; by not going any where for a whole weekend. Starting Friday night to Monday morning, don't shampoo your hair and yes, it will become an oily mess hence the reasoning for staying home. It’s a good time to do your Spring cleaning. By Monday morning, you will be dying to wash your hair, but do not apply conditioner to your scalp. Only apply conditioner from mid-shaft to the ends. Your scalp becomes more oiler with conditioner and all the hair training will be for nothing. After this process, don’t wash your hair any more than every three days. The goal is to work up to washing your hair once a week. Understandably in the summer time this could be a challenge, however once you break your routine, you’ll have to retain your hair. Trust when I tell you, your hair will thank you and you'll feel better that you have finally cleaned out your closets.
Just offering a little of my experience and knowledge.