Dyeing hair can damage it over time. To repair damaged hair after coloring, one should shampoo no more than twice a week to maintain the scalp's natural oils, avoid using hot hair dryers or only use them on low heat settings, brush hair with a wide-toothed comb only when fully dry to prevent breakage, and deeply condition hair weekly by leaving conditioner on for 30 minutes under a shower cap before rinsing with cold water.