This question comes up very often once the car has already been repaired and the owner wants to preserve the result, not just enjoy it for a few days. If the task is to level the appearance, restore gloss, and reduce minor visual defects, polishing does that job very well. If the next priority is easier maintenance, better water behavior, and some added resistance to chemicals and environmental exposure, ceramic coating can be a logical continuation.
But if the main goal is mechanical protection — especially from stones, daily abrasion, and damage in vulnerable front-end areas — PPF is usually the most effective option. Polishing improves the finish that already exists. PPF is better at stopping that fresh result from deteriorating quickly again.
That is why the most practical logic often looks like this: first refine and visually level the repaired surface, then apply PPF to the zones that receive the most impact in daily use. This is especially justified on freshly repainted front-end parts, cars that spend a lot of time on the highway, dark-colored vehicles, and cars whose appearance the owner wants to preserve for as long as possible.