Remember that portrait I did for my friend's wedding gift? I made so many tiny changes to the background shading. At first I just saved the file often, but I messed up the blending and my undo history wasn't enough. That's when I started making layer versions before any shading work, and it saved me from redoing hours of progress. Now I do it for any edit that feels risky, even small ones, because a small change can spiral out of control fast. The clutter in my files is a fair trade for avoiding that panic.