Curious , I Realize with Today's Engines & Technology..My Query is, How far can One safely Travel on a Set of Spark Plugs ?? We have 67,000km Showing and just made it through our 4th Winter in Eastern Ontario.. Averaging just shy of 17,000km driven per year.. The Car has yet to be Plugged In during the Winter Months and sits outside .. Still Runs like a Top and gives Good MPG.. We live in a Rural Setting so it's mostly Highway Mileage..lol..