What is the duration after which a Muslim who abandons prayer is considered an unbeliever by those who hold the view that one who abandons prayer is an unbeliever?

Scholars have differed on the ruling concerning one who abandons prayer out of negligence. Those who hold that abandoning prayer constitutes disbelief have further differed on the extent of abandonment that leads to disbelief. Some said that one disbelieves by abandoning a single prayer. This is the view of seventeen Companions and Tabi'un, among them 'Umar ibn al-Khattab and Ibn Mas'ud. It was also the view of Ahmad ibn Hanbal and Ishaq ibn Rahawayh. Some scholars, such as Ibn Taymiyyah and Ibn 'Uthaymin, chose the view that whoever prays sometimes and abandons it sometimes is not a disbeliever. Rather, only one who abandons prayer entirely is a disbeliever, because the Prophet, peace and blessings be upon him, said: "Between a man and polytheism and disbelief is the abandonment of prayer," and he did not say "the abandonment of a prayer."