Adding guardrails around nested prefabs

If a prefab only exists in one scene, put it in there and save the scene, then NEVER change the scene again, and NEVER edit the prefabs in that scene.

Always edit the prefab by doubleclicking on it and editing it there. That’s your guardrails.

Otherwise, just put everything in additively-loaded scenes with some kind of resource locator pattern once everything is in place.

Some notes on additive scenes:

Additive scene loading is one possible solution:

A multi-scene loader thingy:

My typical Scene Loader:

Other notes on additive scene loading:

Timing of scene loading:

Also, if something exists only in one scene, DO NOT MAKE A PREFAB out of it. It’s a waste of time and needlessly splits your work between two files, the prefab and the scene, leading to many possible errors and edge cases.

Two similar examples of checking if everything is ready to go: