I have frequented “Bob is the oil guy” site for years. I also send oil samples to Blackstone labs for oil analysis. I’ve never had to shorten oil change intervals and pretty much go by the Blackstone lab reports. Our 98 4runner has 240,000 on it, minor issues like belts and one wheel seal. Regular maintenance such as brakes, oil changes and timing belt change. Great vehicle. Sons 99 4Runner has over 350,000, same stuff as mine. We have always used Mobile 1 full synthetic.
I had a used Volkswagen that needed a new clutch every 30k miles, and I was not doing any hot-rodding with it. The Volkswagen clutches were backwards, and that was supposedly part of the problem.
I watched his video about this when he first filmed it. Very interesting product that actually does what it claims to do. I plan on trying this on my brother-in-laws 2006 tacoma that has 270,000 miles and does have some gunk buildup in the valve cover.
Sign up on Valvoline's website. They run BOGOs fairly often. When they do, it's at the cheapest you'll find it.