Carfax is a must nowadays. Ive run probably over 100 carfax reports on cars Ive been considering purchasing in the past 5 years or so. Many, many times it has saved me from buying a car that could have had serious issues or at the least would be hard to resell down the road. Its helped me in determining if sellers are truthful just in simply comparing things like length of ownership, amount of owners, whether they had it maintained at a certain dealership or not etc. But it has also saved me from buying several different vehicles with modified odometers. People dont realize how easy it is to change the mileage of cars these days. They seem to think if it has a digital odometer it cant be altered which just isn't true. I've personally passed on buying lots of cars because I was able to determine the mileage on the cars odometer wasnt the actual mileage, based on recent oil changes and mileages reported by carfax. In one instance I was looking at buying a vehicle that had 96,000 miles on it, I ran a carfax report and found out it was sold years earlier at a dealership with 170,000 miles on it. Thanks Carfax