You have to read all three conditions together. For example, having a room-mate that occupies one bedroom that the family is not using otherwise, even for overnight guests.
Let’s take a look at a bigger example, that of what happens in my house: We have a basement that is 80% developed. The undeveloped 20% is where the hot water heater is, the furnace and storage. The access between the basement and the main floor is unfettered (that is, there is no door. And no, we didn’t take it out, it is designed to have no door). The basement is a walk out. The development has a bedroom and a living room, space for a wet bar but not yet put in. The walkout is the only access to the yard from the house. And through the basement is the only access to the storage. Before our son was 18, he lived downstairs rent free. After 18, he pays rent.
Is there a change in use from PR to rental?f
My argument is no because regardless of size, our use of the space has literally not changed. The fact that he is 18 and paying a rent does not change the use or how we use it.