Shaykh al-Islām was asked:

Are the angels assigned to a servant always the same, or does Allah send down two different angels to him each day? Are some angels assigned to the servant by night and others by day? And what is the meaning of His saying, Mighty and Majestic:

“He is the Subduer above His servants, and He sends guardians over you until, when death comes to one of you, Our messengers take his soul, and they never neglect their duty.”

He replied:

All praise is due to Allah. There are different categories of angels. Some are assigned to the servant permanently. Others alternate by night and day and gather at the dawn and afternoon prayers. He asks them—though He knows best about them—“How did you leave My servants?” They reply, “We came to them while they were praying, and we left them while they were praying.” There are also angels, additional to those who record people’s deeds, who seek out gatherings where Allah is remembered.

(The deeds of the servants are collected both collectively and in detail. The deeds of the night are raised before those of the day, and the deeds of the day before those of the night. Deeds are presented to Allah every Monday and Thursday. All of this is reported in authentic hadiths. As for the claim that the two angels assigned to a person are replaced each day, no report concerning this has reached us. And Allah knows best.