Deep-cleansing shampoos might get a bad rap for being drying , but experts still preach the importance of washing with them regularly to keep your hair and scalp healthy. "Clarifying shampoos are important because over time, oils and ingredients from products sit on your hair and — worse — on your scalp, and can make your hair extremely greasy and hard to manage," says Koni Bennett , stylist and owner of Vanity Salon. "To keep your styles looking fresh, and to avoid irritating your scalp, it's important to regularly remove buildup."