The Prophet (peace and blessings be upon him) said that he sought Allah's forgiveness and repented to Him more than a hundred times a day.
Astaghfirullaha wa atubu ilayh is number 15 of the 16 evening adhkar. It is recited 100 times in the evening. The Prophet (peace and blessings be upon him) said that he sought Allah's forgiveness and repented to Him more than a hundred times a day. Source: Bukhari 6307, Muslim 2702 (Sahih).