Originally Posted by PhenixFord
No doubt that engines are made better and last longer than ever before. I have to wonder if the 10K change interval is designed to assist the service departments?
Toyota, and other manufacturers, recommended 7500 under normal conditions, 5000 under severe service for many, many years.
I traced it back to the late 90s, but was unable to find any maintenance manuals older than around '96.
In the early/mid 2000's, Toyota began adding the "Maintenance Required" light, and it was and remains a simple 5,000 mile timer, unlike the GM and Ford OLM's that actually calculate based on driving conditions.
Multiple members on Toyotanation have submitted 0w20 to Blackstone for analysis and 10k OCI is perfectly acceptable.
If you don't trust it and prefer to stick with 5k, of course, it's certainly not going to hurt anything.
If you don't rack up more than 10k in one year, then annual changes are needed, and I'd go more frequently than that if the engine is not regularly brought up to operating temp and held there for an hour or so to boil off condensation and combustion acids. My wife barely has 30k on her '15 Rav, but a couple if times a month or more she runs a ~40-50 mile trip, she's on her 5th oil change, my '16 Corolla has 77k on it, 8 oil changes.
Lighter oil improves CAFE numbers.
Less frequent maintenance (oil, plugs, etc...) improves JD Powers "36 Month cost of ownership"
The use of Iridium plugs @120k has put plug replacement firmly outside of 36 months, and a non-issue completely for the majority of owners, who trade in every 5-7 years at <120k, while for the owner who keeps the vehicle to 150-200k, the plug change cost is identical for DIY, and cheaper due to reduced labor if they have the dealer do it.