Are there special virtues for reciting "Istighfar" 1,000 times a day?

There is nothing in the Sunnah that indicates the virtue or desirability of seeking forgiveness a specific number of times. However, it was narrated that Abu Hurairah (may Allah be pleased with him) used to seek Allah's forgiveness and repent to Him twelve thousand times day and night. The principle regarding general ذكر (remembrance of Allah) is not to adhere to a specific number, out of fear of innovation (bid'ah) and imitating legislation. It is desirable to increase in seeking forgiveness without specifying a number. However, if a person sets a specific number for himself as a regular litany (wird), there is no harm in that, due to the action of Abu Hurairah, provided that he does not believe there is a special virtue for this number that was not mentioned in the Sunnah, or that persevering in it is a regular Sunnah (Sunnah Ratibah). Rather, he does it to manage his time, accustom himself, and persevere in good deeds.