Where is the break point in driving an old gas hog & the energy spent to make a new efficient car?

Answer 1

I couldn't put a figure on it, but you should keep driving your car as long as possible before getting a new one. A car's body starts to rust and fall apart long before the engine starts burning oil and wasting gas. Buying new cars frequently is a major waste of energy and raw materials and cause of environmental damage. Here in NZ we import used Jap cars that wouldn't get a warrant of fitness there, and some of them are only 3 years old. Their fitness standards are ridiculously stringent.