Quick, how much does it cost to own and operate your car for a year? Based on trading every three years and driving 60,000 total miles, you'll be spending $18,544 annually for your Cadillac STS and $8,004 for a Honda Civic LX according to Runzheimer International. If you need room for the dogs and that all important four by eight sheet of plywood, how about a Ford F350 at $17,967 or a Ford Ranger at $10,113. Most everything else falls somewhere in between.
Don't know what happens after three years. Maybe you just drive them for free 'til the wheels fall off.