Long hair should be trimmed on average every eight to 12 weeks, while medium-length hair should be trimmed every six to eight weeks to maintain the length. Short hair should be trimmed every four to eight weeks to maintain the shape and length.
Individuals with long hair may need to get their hair trimmed more frequently if they have split ends or breakage. Individuals who have medium-length or short hair and want to grow it out can generally wait up to 12 weeks to get the ends trimmed. Frequently colored or processed hair may need to be trimmed more often than uncolored or untreated hair.