Sunan an-Nasa'i · 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
Sahih Lighairihi · Abu GhuddahSahih · Al-AlbaniDaif · Zubair Ali Zai