In most cases people who swap within 3 years are still financing. If your doing it that way odds are your carrying negative equity over or tossing out a decent down payment each time. If your financing your still "renting" the car in a way because you don't own it. If you have the cash to throw down on a new car every few years its still a better move to lease or maybe finance depending on rates, tying up 20k+ in a depreciating product could cast you more than what you can do with that same 20k in a money market. I don't believe it works for everyone but it can be a safe way to buy if the driver understands what they are doing and does it as its set up.