I've been learning about the append and linking function to bring in objects from other Blend files to the current one being worked on, but something keeps nagging at the back of my mind:

Aside from having already created the object for another blender file, why would you not just make the object in the current blend file instead of giving it it's own blend file and then appending/linking it?

Would it not be easier to make the object, say a window on a different layer of the blender file you are working in then copy-link it into the scene on a different layer instead of linking it from an external blender file? Is there any advantage in doing it either way or is it just a personal choice?