There are trailers for cars as well as for vans and trucks on TruckScout24. For the car trailer it is important to check hinges and doors open easily, any tarpaulin is not too brittle, the trailer brakes, if there are any, work correctly and rust is not visible. And like with any motorised vehicle, a test drive is always of value.
If a service book is available, check how often the trailer was serviced. In general it is important to check the axles, undercarriage, brakes and electrics. Also important to check is the condition of the tyres, which can offer valuable clues to the frequency of use and any possible defects. The trailer substructure should also be inspected. Box and Tanker trailers should be checked for water tightness, while refrigerator units in Reefer/Isolated/Freeze trailers should be examined to ensure they are working correctly and have been regularly maintained. Lowbed trailers should be inspected for physical damage in the trailer structure. Finally, it is important to ask what the trailer was used for in the past as this can also affect the general condition of the trailer.