I have had the view for many years that Sri Lanka was closer to the Buddha's teachings on one point than Thailand or Burma or Cambodia. Thailand, Burma and Cambodia allow temporary ordinations, where a man is ordained as a monk with the intention of giving up the robes and returning to lay life after a period of time, commonly three days or three months. Sri Lanka, as a general rule, does not, although there are individual teachers who will ordain a person for one week.
Although no one disputes that the Buddha allowed monks to give up the robes and return to the lower life (there are a fair amount of instances of this in the Tipitika), there is nowhere, at least that I had come across, a record of him ordaining anyone who had the intention to return to lay life. The Buddha's intention in instituting the bhikkhu Sangha was clear - the person renounced the life of householders and went forth into the holy homeless life. (It is still called the homeless life, even though it was only in the first ten years or so that all monks were literally homeless, wandering from place to place, sleeping under trees or on rocks. The Buddha then allowed monks to stay in dwellings offered to them by the laypeople, and almost all monks nowadays do. Some restrictions apply.)
The Apadana is a book in the Khuddaka Nikaya that had so far gone untranslated into English. A few years back, however, Prof. Jonathan Walters published online his translation, Legends of the Buddhist Saints, in 2018. Since it had never been printed, I obtained his permission (which, by the Creative Commons license he released it under, was not strictly necessary) and have printed a number of copies of the first two volumes. (Please contact me if you would like one free of charge.)
I recently came across a sutta in it, 288. Sattahāpabbajita (Renouncer for a Week). The Apadana is about the previous lives of many different arahants under Sakyamuni Buddha, and their small acts of good merit under previous Buddhas, who experienced the fruits of their actions and who eventually became arahants (enlightened people) under Sakyamuni Buddha. Most of the suttas in the Apadana are about small acts of generosity towards a previous Buddha. A few are about other meritorious actions. In this sutta, Sattahāpabbajita went forth (a standard Tipitika term for becoming a novice monk) for a week (!) after a rift among his family members.
The fruit of this week as a novice (samanera) was that for the ninety-one aeons since he has not had a bad rebirth. He declares that's the fruit of (a week's) renunciation. And then in his last life, under Sakyamuni Buddha, he becomes an arahant.
So we have a clear Tipitika foundation for temporary ordinations, at least as a novice.
This is one of the things I like about reading the Tipitika directly rather than books about dhamma by later authors. One finds hidden gems that make things clear.