It is for all time and is not invalidated by delaying it until the day of Eid al-Fitr, even if the duration is long; because the command to perform it is unrestricted by time, so it must be performed at any time other than a specific time, and it is specified by performing it in action or at the end of life. It is obligatory in a broad sense throughout life, like zakat, vows, expiations, and similar matters according to the correct opinion; because the command to perform it is unrestricted by time, so the obligation does not narrow except at the end of life, like the command regarding zakat and other commands that are unrestricted by time. See: Sharh Mulla Maskin p. 67, and Al-Badai 2: 74.