It depends on the car you own, the one you are buying and how much you drive. If you don't drive a lot and have a fuel efficient car, keep the car. If you own

It depends on the car you own, the one you are buying and how much you drive. If you don't drive a lot and have a fuel efficient car, keep the car. If you own a Land Rover and drive a lot, buying a Tesla you'd be up over a few years. http://www.greencarreports.com/news/1093657_buying-a-new-car-is-greener-than-driving-an-old-one-really http://www.greencarreports.com/news/1093657_buying-a-new-car...