It's a well known fact in Islam that faith (iman) fluctuates up and down, which is natural. Prophet Muhammad (ﷺ) said, "Faith wears out in your heart as clothes wear out, so ask Allah to renew the faith in your hearts" (Mustadrak). So we go through highs and lows. If a Muslim is going through a period of 'low faith' then he should make the dua as suggested by the Prophet (ﷺ), continue with prayers and do more voluntarily good deeds that will increase his faith. Our actions have an influence on our faith.
A Muslim should not let faith get so low that he stops practicing Islam.. because this puts him at danger of disbelief. For example, Prophet Muhammad (ﷺ) said, العهد الذي بيننا وبينهم الصلاة، فمن تركها فقد كفر (The covenant that stands between us [Muslims] and them [disbelievers/hypocrites] is prayer, so whoever abandons it has committed disbelief) - Al Nasai, Ibn Majah, Tirmidhi. This refers to giving up prayer all or majority of the time. Hence, a Muslim low on faith should never abandon prayer. That is the worst mistake!
Although faith fluctuations are normal, "falling out of religion" i.e., abandoning it is not a cycle that is seen as normal within Islam nor is it acceptable. It's actually condemned by Allah (ﷻ) who said, "Indeed, those who have believed then disbelieved, then believed, then disbelieved, and then increased in disbelief - never will Allah forgive them, nor will He guide them to a way" (Qur'an 4:137).