Noticing this, I said to him, “Why are you taking the trouble of waking up to do whatever work you wish? Why do you not wake me up so that I can serve you and assist you?” Imaam Bukhaari (rahimahullah) replied, “You are still young, so I do not wish to disturb your sleep.”
Muhammed bin Abi Haatim (rahimahullah) further mentioned that at the time of sehri, Imaam Bukhaari (rahimahullah) would perform tahajjud salaah followed by his witr salaah.
He also mentioned that Imaam Bukhaari (rahimahullah) possessed some of the blessed hair of Rasulullah (sallallahu ‘alaihi wasallam) which he would keep with him in his clothing (so that he could derive blessings and barakah from it).
(Hadyus Saari pg. 481)