Must one make up missed prayers, no matter how numerous, or do they lapse and one suffices with performing Sunnah and supererogatory prayers, claiming that their time has passed and that "good deeds efface bad deeds"?

Scholars differed regarding making up intentionally missed prayers. The majority held that it is obligatory to make them up, which is the more cautious approach and clears one's conscience. However, the Zahiris and Ibn Taymiyyah were of the opinion that they cannot be made up, and that what is obligatory is sincere repentance and increasing in supererogatory (nafl) prayers. What we issue fatwa on is the obligation of making them up. And for the common person, it is permissible to follow whichever scholar he trusts in their knowledge and piety when there is a difference of opinion among them.