Bought a 2006 Limited version AWD Ford 500 in 2018 at 210,000 miles, mostly highway miles. Single owner, a woman, who did limited service on it, but is in excellent condition. Tranny fluid was unserviced, so I did two drain and fills pretty quickly.

The ignition system looks original, so this week I contacted to prior owner and asked if spark plugs had ever been changed. "No, not that I recall."

So I've now 230,000 miles on the original plugs. It runs fine. Question: should I replace the stock plugs even though they are working.
My usual approach is - if it's not broke, don't fix it. But never heard of 230,000 on original plugs before.

... 'Tis mild call for advice here.

 

A suggestion, what if you removed one or two of the spark plugs and looked them over ?
If the gap is really large it could be putting a strain on the ign system. Maybe they did change them and don't recall. What you see will tell you what you should do.