Watched a guy spend 45 minutes feathering a quarter panel when it needed 3 hits with a body hammer first
He was chasing tiny dents with 180 grit on a DA at my shop in Fresno last Tuesday when the metal was still stretched and proud, and once he roughed it back into shape with a hammer and dolly the filler work took him 10 minutes, so what's the tell you use to know when a panel needs metal work before any sanding?