So, I'd like to know how, (in the "olden days"), the powers-that-be proclaimed:
Thou shalt not go beyond 3000 miles in thee's oil change interval.
Was there some sort of testing, or did oil just "look dark enough" at that point. I think it was when garages would pump your gas, check the oil, etc., that the notion was driven home: sell more oil changes, filters, and oil.
I grew up with my parents having that mentality -- older cars maybe needed it. But now, with processors that calculate the oil life based on numerous variables in engines with stricter tolerances and better build quality:
In many cases, it would be more expensive to change the oil at 3000 miles for the life of the car than to replace the entire engine
I fully expect newer cars to run on whatever lubricant, dino or synth, for 5000-7500 miles without friction-related failure for 150K miles+. I know someone who didn't change the oil in her '98 Camry for 25,000 miles (or what oil was left -- she just added some now and then). The car is still running today! Granted the dealer flushed it when it wasn't "running right", but she reported a huge increase in fuel economy
It probably has over 150K on it now.
That's an extreme/outlier. Let's say you drive 15,000 miles a year, and the average oil change/filter over 10 years is $30.
At 3000 miles, that's 5 changes a year X $30 per change X 10 years = $1500 for 150,000 miles.
At 7500 miles, that's 2 changes a year X $30 per change X 10 years = $600 for 150,000 miles.
I can think of a few things other than oil to spend $1100 on.
If the oil change is more expensive, then the benefits are even better -- crunch some numbers to find out. You might be able to have enough for a brand-new engine at 200,000 miles!
RH77