I'm on my 3rd Bosch sensor in 4 years. While leaded fuel will send them south I think the real enemy is moisture and cold start up. I built a guard around where my exhaust dumps into the tunnel to help keep the snow out and it seems to have helped make the sensors last better. If they get wet and you fire up the sled in the morning it cracks the ceramic inside the sensor if there's moisture in the tip. I also think the heated trailer at night helps prolong them, but bottom line is I expect to cook 1 sensor a year.
M5
M5