Hadith 5057
أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا بِشْرٌ، عَنْ يُونُسَ، عَنِ الْحَسَنِ، وَمُحَمَّدٍ، قَالاَ التَّرَجُّلُ غِبٌّ .
It was narrated that Al-Hasan and Muhammad said:
"Combing one's hair (should be done) every other day."
Reference : Sunan an-Nasa'i 5057
In-book reference : Book 48, Hadith 18