While a brand new car has its attractions, many people have found that a car with some mileage on it runs just as well, has had the kinks worked out, and costs a lot less than a new vehicle. So it goes with dogs. A mature dog usually has plenty of life left. In addition, the behavioral kinks have likely been taken care of, and a mature dog often costs a lot less than a 2- to 3-month-old puppy. The advantages break down as follows.