It is not like the obligatory prayer, but it is a Sunnah that was done by the Messenger of Allah ﷺ and his Companions, and they continued doing it until the end of their lives.
أَمَّا كَالْفَرِيضَةِ فَلَا وَلَكِنَّهَا سُنَّةٌ صَنَعَهَا رَسُولُ اللهِ ﷺ وَأَصْحَابُهُ حَتَّى مَضَوْا عَلَى ذَلِكَ