Musabbih bin Sa’eed (rahimahullah) reports the following:
On the first night of Ramadhaan, Imaam Bukhaari (rahimahullah) would lead the people in Taraweeh Salaah. Imaam Bukhaari (rahimahullah) would recite approximately twenty verses in each rakaat, and would continue each night until he eventually completed reciting the Qur’aan Majeed.
At the time of sehri, he would recite between a half to a third of the Qur’aan Majeed in Tahajjud Salaah. In this manner, he would complete one khatam in Tahajjud Salaah every three days.
Over and above this, Imaam Bukhaari (rahimahullah) would make one khatam daily, during the day, and would complete it at the time of iftaar. On completing the khatam, he would engage in du‘aa and say, “At the time when a khatam is completed, du‘aas are accepted.”
(Tahzeeb-ul-Kamaal 24/446)