Some — but not all — low-priced products give your hair that silky feeling and light-reflecting gloss by coating the shaft with a wax, which doesn't always wash off completely. The result is a buildup that can keep hair from absorbing color or holding styles, dandruff, and breakage. During this time of year, piling on serum, spray, gel, cream, and mousse to protect hair from the wind and dry air can actually make it even drier.

According to New York City stylist Antonio Prieto, a common cause is using a larger quantity of styling products than recommended, especially if the product has alcohol high on its ingredient list. His solution? Use a clarifying shampoo and higher-quality stylers, especially ones with water soluble ingredients. Try washing hair with Bumble & bumble Sunday Shampoo ($18 for eight ounces), which removes residue, hard water minerals (another cause of dullness), and pollutants, or Frederic Fekkai Apple Cider Clarifying Shampoo ($23 for eight ounces), which rinses out buildup while nourishing with apple, verbena, rosemary, and kukui nut oil. Those with color-treated hair might stick to an even more natural shampoo, since it probably won't include stripping sulfates, like EO Clarifying French Lavender Shampoo ($6.59 for eight ounces).