I have seen part files that are broken up into such a system - all sketches on a certain layer, sheet bodies on their layer, solid bodies on a layer, etc etc. What is the advantage to such a system?
When I get to determine layer structure I usually group all related entities that make up a certain feature set on a layer. For instance, if I want to add a 'widget' feature, I'll put all the geometry, the extrusion (or revolve, whatever), and any necessary trim sheets on layer 'widget'. That way when I want to edit feature widget I just turn on that layer and all the necessary geometry is there.
Is it just a standards thing or does it make the file easier to edit later? If it will make life easier I'm all for it, please educate me.