Fine sand is abrasive. Tracked in on shoes, it acts like sandpaper underfoot, which is why traffic lanes dull long before the edges of a room do.
Acidic cleaners are the main cause of etching. Anything citrus or vinegar-based will dull marble permanently, and no amount of buffing brings back an etched surface without regrinding.
Use a neutral pH cleaner and change the water often. Dirty mop water redeposits the same grit you just lifted, which is a slow abrasion cycle most homes run daily.
Seal, then reseal. An impregnating sealer resists oil and water but wears at the traffic lanes first, and water no longer beading is the signal it is due.
Polishing is not a coating. Genuine polishing removes a fine layer of stone so the shine is the stone itself. A coating sitting on top will eventually peel, and peeling is far harder to correct.
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Inspection, written scope, photo report on completion. Send us a message and we will confirm an inspection slot, usually the same day.