What's best way being able to return to non filleted or unioned objects?

I have had to overcome these, some now solved:-

What to do to V5 dims in existing files for open into V7? - #3 by Steve1 solved
What settings to make shaded same V7 and V5? - #7 by wim solved
Draw line on Y axis shows either side of Green
Rhino V7 (WIN) vs. V5, why does my line anti-alising look trash? - #10 by Steve1
What model space scale should default Rhino V7 be? - #3 by Steve1
V7 circle selected it get UNWANTED control points dashed line box - #3 by Steve1 solved
What setting to stop lines looking like twisted ribbons v7? - #3 by Steve1