How long do I need to have owned my car before selling it to a dealer with Autotrader? You'll need to have owned the car for a minimum of six months before using this service. Related articles How long does it take to sell to a dealer? Can I sell a vehicle to a dealer for someone else? Can I change my mind about selling to a dealer and cancel before the listing ends? Can I advertise my vehicle on Autotrader and have a listing to sell to a dealer at the same time? Is an MOT required to sell to a dealer?