How long do I need to have owned my car before selling it at auction? You'll need to have owned the car for a minimum of six months before using this service. Related articles How long does the auction take? Can I change my mind and cancel before the auction ends? Can I sell a vehicle via auction for a relative who has passed away? Can I advertise my vehicle on Auto Trader and have an auction listing at the same time? Is an MOT required to sell at auction?