I'm sure your right there. All objects really just exist in the same place and it's just the visibility that is turned on and off with layers. But isn't it common in modeling to select parts of some object and copy and paste them, leaving the original intact and just having the copied bits as separate objects? Forget the layers issue, that's really what I have been trying to do.

I just discovered that if you duplicate a group in the outliner, the duplicated group is automatically added to what ever layer is currently selected. That's quite handy, I can create an empty layer and when I duplicate, the new group is automatically in there.

Yes I will try to find a good total workflow tutorial, there's probably some in Simply Maya I should look at.