How can I get better mileage with the Smart Edge thingy?

Special tip: Promote that image from background to layer first so you can righclick your Eraser Tool & redraw/rebuild any missing areas in your subject that got cut away with a selection tool.  If we've been working on a layer & accidently hacked away too much with any selection tool we can magically paint it right back on by rightclicking the Eraser tool.

We're on a layer meticulously removing background from a subject when
we realize during feverish zoomed-in activity we've accidentally cut away
something we really didn't mean to.  It's a color adjusted copy so going back to the original to Copy & Paste a new chunk won't match.

We already cut away a bunch of additional background after
that section ... so using undos to back out of this screw up wipes out a lot of
other work too. Crap.

All is not lost. We're on a layer and the ERASER is a friend.

We didn't even use the eraser to cut away that background we used selections
... but when we Rightclick with the eraser tool we can still redraw/replace
those missing portions of the image in the same way as if it had been erased.

Thank you eraser tool.