Just realized I've never changed my spark plugs since I purchased my Escape with 42,000 km (25,000 miles) on it. I now have 95,000 km (60,000 miles). I see that the job is a bit more complicated with removal of the intake manifold required on the V6. I've detected no hesitation or misfires, so, maybe it's too early to get into a job like that. Some say, if it's not broken, don't fix it. I do like to tinker, though.