We recommend shampooing and conditioning the hair at least once a week using professional grade products. If you have Clip-On extensions this will be about every fourth wear. Since the hair is no longer attached to a live root, properly cleansing and conditioning your extensions is crucial.
Over shampooing (more than 3-4 times a week) will lead to drying out the hair.
Under shampooing (less than once a week) can lead to build up, which will cause tangling and matting.