Tldr: The title lol.
I have a 99 Chevy s10 2.2, and it has been running synthetic blend oils (5w-30). It is at 112k miles. And since I am doing my own oil changes, I noticed that blends and full are damn near the same price.
I have been doing 5k intervals with blend, should I go to a 7.5k interval with a full? My truck has a highway maintance schedule in the manual that says it could do 7.5k going by highway miles. I drive mostly highway (speed limit near me goes to 45 at the lowest).
I am one of those people that changes synthetic oil and filter every 10,000 miles. All of my vehicles have gone at least 15 years and 165,000 miles with extended drain intervals. Old habits like to 3,000 and 5,000 mile changes are hard to break. That said, many here will say oil is cheap. True. My time is a factor as well. You know better than anyone else how the car is driven.