When your scene is structured with objects in different layers using the Display Layer Editor, you can organize related elements of your scene and selectively make them visible or invisible in the 3D view, and make them selectable or not.
By turning the visibility of a layer on or off, you can see these objects in the 3D view only when you need to. As well, you can hide objects in a layer only during animation playback, which can make the playback go faster.
Using layers also enables you to template or reference all objects in a given layer, which makes them unselectable. This prevents you from accidentally selecting or changing any of these objects.
