When you build a world and put houses, caves, etc into it, you could just place that stuff inside the main scene and hide/ unhide it or change the scene completely.
Thinking about it, I guess the size of the new scene, the amount of objects inside it, etc. have a big influence on the decision.
I guess hiding/ unhiding makes more sense on small scenes (for example a house with a npc) and changing the scene is like going to a new level (for example a huge cave system).
But are there general rules of thumb for cases which are not as clear (tiny house vs huge cave)?