(48) The Book of Adornment
كتاب الزينة من السنن
(7) Chapter: Combing the Hair Every Other Day
(7) باب التَّرَجُّلِ غِبًّا ‏‏
Sunan an-Nasa'i 5057 
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 ‏.‏
Grade :  Da'if (Darussalam)
Reference : Sunan an-Nasa'i 5057
In-book reference : Book 48, Hadith 18
English translation : Vol. 6, Book 48, Hadith 5060