Or your newer vehicle if the engine is expensive enough to warrant the money and it's not a run-of-the-mill vehicle operating under nominal conditions.

I wouldn't bother for a daily driver that's not being thrashed and trashed. I went 30,000 miles on my last oil change due to heavy usage and the numbers weren't too bad but I usually try to change it around 15,000 to 20,000 miles. The report below is for a Cummins ISB 6.7L diesel that we bought new in 2013 that really only sees highway miles. I'm about ready to do my fifth oil change on this unit.

Not sure how well the text will display in this report.

I wonder, would an engine oil analysis before buying a used vehicle be a good idea?

$25 for some piece of mind.

Seller might take offense. Although the history is probably more important than a single snapshot.

I like the idea of offending a used car dealer.

Wear a plaid suit with wide lapels and wingtip shoes and ask for a job selling cars.