Hair extensions consist of human hair and need nourishing care. Like your natural hair, hair extensions can dry out, get split ends and can be brittle. Though the hair is no longer nourished through the hair root, it will depend on how you care for your hair extensions and how beautiful they will look on your hair. When you apply hair extensions, you should wash your hair less often. Depending on how oily your scalp is, you can wash your hair extensions around two to three times a week. In between this timeline, you should use dry shampoo to absorb additional amount of oils.