When is wet sanding used on car paint, and when is it too risky?

Wet sanding is used to level deep scratches and flaws that polishing cannot remove efficiently, such as deep scratches, heavy orange peel, runs in fresh paint and some etching. It removes significantly more clear coat than polishing, so it should only be done where paint thickness has been measured and enough material remains. Factory paint is often too thin for safe wet sanding on edges, and the sanding marks must always be fully polished out afterward.