How often should a ceramic coating be reapplied to a car?
Quick answer: Rarely -- a quality ceramic coating is a one-off that lasts years. Keep it clean, add a compatible maintenance spray when performance dips, and only re-coat when there is a clear reason.
It depends on the coating you have and how much abuse it sees.
A retail ceramic product applied at home -- bought online or from a motor accessory shop -- will usually need reapplying every six to twelve months.
A professionally applied ceramic coating should last many times longer.
A garaged car doing three thousand miles a year will hold a coating far longer than one covering serious motorway miles. Before we can say when yours needs reapplying, we have to ask how long it will last in the first place. The conclusion there is that it probably lasts much longer than you think.
A useful way to picture it is as a half-life. Buy a 5-year coating and, under average use, after five years it has lost about half its protection. Is half the protection adequate? It might be -- but it is not optimal.
A better question, then, is: how will I know when it needs reapplying?
The answer is when it stops doing what it is supposed to do. The first sign is usually loss of the hydrophobic effect. Wash marring showing through is another cue that the surface needs attention. If a thorough wash and decontamination do not restore performance, the coating itself is likely the issue -- see how to tell if your coating is working for the diagnosis.
You can extend the life of a professional coating with top-up products, and we'd recommend it. Mark the calendar for one top-up a year, have a professional deal with scratches and stone chips as they happen, and you may keep the coating going indefinitely without ever needing a full reapplication.
The genuine cases for reapplication are narrower than people expect: machine polishing a panel removes the coating in that area, so the panel needs re-coating afterwards. Paint repair or refinishing means the new panel needs coating. And after several years of real use, the coating may genuinely have worn through. None of those reasons run on a fixed annual calendar.