Abu Salamah bin Abdur Rahman (may Allah have mercy on him) says: I went to Umm al-Mu'mineen, Lady Aisha (may Allah be pleased with her), and asked: "Mother, tell me about the fasts of the Messenger of Allah (ﷺ)." She said: "The Messenger of Allah (ﷺ) would fast (voluntary fasts) in such succession that we would say he will continue fasting, and he would break his fasts until we would say he has stopped fasting altogether. I never saw the Prophet (ﷺ) fast in any month more than in Sha'ban (it was as if he spent the whole month fasting, leaving only a few days)."
Hadith Referenceالسنن المأثورة / باب صيام من أصبح جنبا / 314
Hadith Takhrijصحيح مسلم، الصوم، باب صيام النبي في غير رمضان، رقم : 1156