...but the wider the gap, the more stress it puts on the coil(s), causing the insulation to burn out internally. If you're gonna run them longer than the recommended interval, they need to be re-gapped a few times.

 

I disagree if not under regular duty use

I agree mostly, the gap is increased by the material eroding away



so to all if anyone wonders, I did go ahead and swap them. I am Kinda disappointed in the check your owners manual post, I was asking more for real world experience because we all know the manufacture knows best when the put it in the “book”

MY tuned truck with 60k, towing 10k of that that plugs were all gapped at .060 +\- .01 and you can clearly see in my picture how the metal it thinner. So in my opinion under these conditions the plugs should be changed, I went with the motorcraft sp548 gapped at .50