I know for more recent vehicles that is probably true, but as an owner of a 2006 F-150 with the 5.4L 3V Triton V8 that had the infamous spark plug issue, I had

I know for more recent vehicles that is probably true, but as an owner of a 2006 F-150 with the 5.4L 3V Triton V8 that had the infamous spark plug issue, I had to lol with a tinge of sadness at your "last 15 years" comment. Backstory: Ford came out the gate with a new spark plug design for the 2004 F-150 3V Triton 5.4L V8 engine (after their previous spark plug design failure in the 2V Triton where the plugs would shoot out) and told everyone that the spark plugs would last 100k miles. Turns out if you let them go that long, they would get stuck in the cylinder head and break off when you tried to remove them, leaving stuck broken pieces of spark plug behind. Conveniently, 100k miles happens to be when most people's warranty expires, leaving people with a best case a few-hundred-dollars-extra tune-up bill, if not thousands of dollars if the heads had to be removed. Ford faced a class-action lawsuit over this debacle, and there are still companies selling special broken spark plug removal kits designed solely for this engine to this day. Of course the root cause of the problem is faulty design, but it would have been mostly avoided had they not claimed a 100k mile service interval for the plugs. So yes, Ford went from an engine where the spark plugs would shoot out of the cylinder head, to one where they would get stuck so hard they would break. I know all of this not because I am an engine geek, but because it happened to me. Two spark plugs broke off while being removed and I came this close to needing to have the heads removed and machined. Fortunately those special removal kits I mentioned earlier really do work. Given how relatively cheap spark plugs are, you can bet it will be a while before I trust that 100k mile number :-)