I can't recall the oil guy that Adam Carolla had on his podcast a few years back, but he was really knowledgeable. Basically, short of full analysis each time, if the oil looks bad, it's usually bad. If it still looks good, it's usually still good.
I didn't see any real correlation between problems or premature wear and oil change frequency, so long as it wasn't over spec. when I researched the purchase this year.
You could put the time into almost anything and the money into warranty if you were worried. Do as you wish, of course. Just saying how I'm playing it.
I don't normally waste money on a warranty, but got the extended - just too many gadgets and gizmos.