Guide
Host presence rules: the lever no permit gets round
Updated
Most people researching short-term rental rules are looking for a permit process. In the cities with the strictest regimes there is a permit process, and it is not the thing that decides the answer.
What the requirement says
New York City's guidance is the clearest published example. Short-term rentals are "only permitted if you are staying in the same unit or apartment as your guests". Not the same building, not nearby: the same unit.
It comes with two supporting conditions that close the obvious workarounds. A maximum of "two paying guests at a time", and a requirement that "your guests have access to all parts of the dwelling unit", with privacy locks on a bathroom or bedroom acceptable but locks that keep guests out of rooms defeating the common-household requirement.
Why it is the decisive lever
Because it removes a use rather than pricing it. A registration requirement can be satisfied by paying a fee and filing a form. A presence requirement cannot be satisfied by anything except being there.
That is why reading a city's rules in the wrong order wastes so much time. Somebody researching the permit process for a whole-apartment let in New York is researching a process that will not become available to them.
Where the primary residence version bites
A softer variant restricts short-term letting to a host's primary residence without requiring presence during every stay, which permits letting the whole home while you are away and prohibits a dedicated investment property.
Where that applies, the definition of primary residence is the thing to read. Some cities define it by days of occupancy, others by documents such as a voter registration, a driving licence and a tax return address. The two tests can give different answers for the same person.
What to check first
Whether the city has a presence or primary-residence requirement, before anything about permits. It takes one search and it determines whether the rest of the research is worth doing.
And whether your specific unit type is excluded outright. New York City lists categories that cannot be registered at all, including rent-controlled, rent-stabilized and NYCHA apartments, entire units in one and two family homes, and units on the Prohibited Buildings List.