What’s the Sunnah way of doing I’tikaaf?
Whoever would like to follow the example of the Prophet (peace and blessings of Allaah be upon him) in observing i’tikaaf during the last ten nights of Ramadaan should enter the mosque before the sun sets on the night of the twenty-first, so that he will not miss any of it, and he should come out after the sun sets on the night of Eid, whether the month is twenty-nine days or thirty.