An insurance write-off marker tells you that an insurer previously decided a vehicle fell into a defined salvage category after damage. It does not by itself tell you the quality of any later repair, so buyers need to understand both the category and the individual car.
Category A vehicles are intended to be crushed and should not return to the road. Category B vehicles have a body shell that should be crushed, although certain usable parts may be recovered. These are fundamentally different from repairable categories.
Category S indicates structural damage where the vehicle may be repaired and returned to the road. Structural repairs make the quality of workmanship, alignment and supporting documentation especially important. A professional independent inspection can be valuable before purchase.
Category N is used where the insurer classified the damage as non-structural. That does not mean the damage was trivial. Steering, suspension, electrical systems and other components can still be significant, and the repair standard still matters.
If you are considering a previously written-off car, ask for photographs of the damage, repair invoices, details of who carried out the work and any inspection or alignment evidence. Compare the price with equivalent vehicles that do not have a write-off history because the marker can affect future value, insurance and resale.
A history check should be treated as a trigger for better questions. If a write-off marker is present, understand exactly what happened before deciding whether the price properly reflects the additional uncertainty.