i think overall care for your vehicle dictates its life span (at least relatively compared to it and its sister cars). and some things go bad due to the make and model ( like how ford f 150, explorers, and rangers eat thier ball joints at 40,000, or the focus's screwed up suspension setup) also the design. others to the climate > salted roads, coastal areas, high altitude. i figure if you know what you are doing your car can last forever... and as long as you replace the little things.... gaskets, and other wearable or degradable things.