True, with one caveat: the engine manufacturer optimized for miles covered under warranty. Some even spec longer intervals between oil changes as a selling poin

True, with one caveat: the engine manufacturer optimized for miles covered under warranty. Some even spec longer intervals between oil changes as a selling point. Some engines are known to be more finicky to dirt (VW infamous chain tensioner comes to mind), and thus it makes sense, if you plan to keep the engine after the warranty expires, to reduce the oil change interval, as oil tends to be much cheaper than an engine rebuild. There's a service where you'd send your spent oil to be analyzed for cleanliness, so you could determine the best change interval for your engine and usage. But that cost of that service wasn't much cheaper than just changing the oil a bit more often…