It was narrated that Al-Hasan and Muhammad said:
"Combing one's hair (should be done) every other day."
أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا بِشْرٌ، عَنْ يُونُسَ، عَنِ الْحَسَنِ، وَمُحَمَّدٍ، قَالاَ التَّرَجُّلُ غِبٌّ .
• Sunan an-Nasa'i, 5057
• Sunan an-Nasa'i, Vol. 6, Book of Adornment, Hadith 5060
• Sunan an-Nasa'i, Book of Adornment, Hadith 5060