Abu Salamah says: I asked Sayyidah Aishah (may Allah be pleased with her) about the fasting of the Messenger of Allah (peace and blessings be upon him). She said: He used to fast until we would say: he will only keep fasting. And when he went without fasting, we would say that he will only keep not fasting. And I never saw him fast more in any month than in Sha'ban. He would fast the whole of Sha'ban except for a few days.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8428