I saw when the Messenger of Allah ﷺ got his hair cut by the barber, his Companions came round him and they eagerly wanted that no hair should fall but in the hand of a person. (Using translation from Muslim 2325)
رَأَيْتُ رَسُولَ اللهِ ﷺ وَالْحَلَّاقُ يَحْلِقُهُ وَقَدْ أَطَافَ بِهِ أَصْحَابُهُ مَا يُرِيدُونَ أَنْ تَقَعَ شَعَرَةٌ إِلَّا فِي يَدِ رَجُلٍ