Umm al-Mu'minin Sayyida Hafsa (may Allah be pleased with her) said: I never saw the Messenger of Allah (peace and blessings be upon him) performing voluntary prayers while sitting, until one year before his passing, he began to perform voluntary prayers while sitting. He would recite the surah with measured recitation (tarteel), so much so that due to his tarteel, that surah would become longer than a surah that was actually longer than it.