If you are buying from a used car dealer, get the VIN number and then YOU run a used car sales package on it. Then you can see if it was owned by many people or had a crash. The dealers will LIE to you about everything about the car.
This is terrible advice. It is not the 1970s anymore.
Dealers are regulated by Omvic now and are absolutely mandated to disclose the history of the vehicle, including the number of owners and if its had any accidents.
A Carfax is available for free for every used car being sold at a dealership in Ontario and any dealers that don’t do that are running the risk of being fined and/ or having their license to sell cars revoked.
Private sale? Yes, absolutely purchase a used vehicle information package from service Ontario.