Istighfar means asking Allah for forgiveness, usually with the words Astaghfirullah ('I seek Allah's forgiveness'). It is not only for major sins; even the Prophet, who was protected from sin, said, 'By Allah, I seek Allah's forgiveness and repent to Him more than seventy times a day' (Sahih al-Bukhari 6307) — showing that istighfar is a constant posture of humility, not a one-time cure. The Quran ties istighfar to real, tangible blessings: in Surah Nuh, the Prophet Nuh tells his people, 'Seek forgiveness from your Lord; indeed, He is ever Forgiving. He will send [rain from] the sky upon you in showers and give you increase in wealth and children' (71:10). Scholars describe istighfar as opening doors of provision, ease, and relief from worry that may otherwise stay closed. There's no fixed limit — it can be said walking, working, before sleeping, after sinning, or simply as background dhikr throughout the day. Many Muslims aim for at least a hundred times daily, following the Prophet's example, without ever treating it as a mere formality; it should carry real regret over sin and a genuine intention not to return to it.
Q&A · Dua & Dhikr
What is istighfar, and how often should a Muslim seek forgiveness?
References
Sahih al-Bukhari 630771:10
Informational, not a personal fatwa. Consult a qualified scholar for rulings on your situation.