It was narrated that Abu Hurairah said: “The Prophet (ﷺ) used to observe I’tikaf for ten days every year. In the year in which he passed away, he observed I’tikaf for twenty days. And the Qur’an would be reviewed with him once every year, but in the year in which he passed away, it was reviewed with him twice.”

It was narrated from Ubayy bin Ka’b that: The Prophet (ﷺ) used to spend the last ten days of Ramadan in I’tikaf. One year he was traveling, so the following year he spent twenty days in I’tikaf.