When should rusted body parts get the heave ho?

I used to do all of my own body work. I had time to fix dents and rust correctly myself. If you are paying a body man to do it, I'd look to see if the panel is re-popped from companies like AMD. If not, I would then look for nice rust free panels i could find. Dents don't bother me as much as rust does.

There is one thing you want to avoid if you are paying someone else to repair your rusted and dented up bodywork. They will charge you anywhere from $50-150 hr. And who knows if they didn't just slather it in bondo and kick it out the door to you.