Does a vow to pray the regular Sunnah prayers daily for life, contingent upon the ease of the matter, one's mood, and physical comfort, become binding, and must it be fulfilled?

A Muslim is obligated to fulfill his vow in the manner in which he vowed it, based on the words of the Almighty: "And let them fulfill their vows," and the saying of the Prophet, peace and blessings be upon him: "Whoever vows to obey Allah, let him obey Him." Thus, the one who made the vow must commit to performing some of the regular Sunnah prayers daily, according to his ability and throughout his life, because a vow must be fulfilled in the manner in which it was made, and the fact that his situation is not stable does not prevent its fulfillment.