Is it obligatory for one who was committing grave sins and repented to abandon them all at once or gradually?

Repentance is obligatory upon every believer, as Allah Almighty says: "And turn to Allah all of you, O believers, that you may succeed," and His saying: "O you who have believed, repent to Allah with sincere repentance." Repentance has three conditions: abandoning the sin, regretting it, and resolving never to return to it. Repentance is not achieved gradually; rather, one must abandon the disobedience immediately, for procrastination is a danger that ensnares a person in the devil's traps.