- Why do you need to set aside time to a check vehicle history report that you can get from Carfax? This Car fax document that is obtainable through carfax.com can be your best bet to ensure you don't become a victim of VIN cloning or you don't fall trap to buying a used car with serious mechanical problems. In short, knowing the history of a vehicle, along with other carfacts can help ensure that you get the best car deal.