I used to really fret about this but am quite relaxed now. Pitting is where the case hardened layer has eroded. do inspect with a magnifying glass to see what’s happening, and I do a very careful reset of the cups. A couple of things.
Don’t overfill with grease - there’s a discussion that excess grease bridging the inside and outside of the hub does recirculate around the seals dragging dirt into the bearing.
Make sure all seals are good. Replace if not, if they are available. I scrounge come seals from spare axles if they’ve gone missing.
Do use high quality grease - eg white Finish Line.
Do use expensive balls - eg campag. They select their balls, other companies do not.
Set the bearings so that the tightest part of the rotation is not too tight. It’s too tight if - when spun whilst being held by two hands the wheel slows at a particular point. It should rotate until a point where it reverses and the valve (when you have tube and tyre on) settles at the lowest point.
Weirdly, one of the world’s most experienced wheel builders told me to set bearings very very slightly loose, and they then tighten in the frame when you do up the QR. And they do. Still don’t quite understand why locknuts and cones move at all on the threads, but they do tighten up, just a weeny bit.
And I’ve got wheels which I thought were entirely screwed, which have gone on for over a decade.....