@Vladimir2306
I look at things like the glass half full. I would rather OVER maintain, than UNDER maintain.
There are things that do not always appear as they are even with an oil analysis. Things like fuel and water contamination in the engine oil are always a moving target. The problem with oil is of you let it go too long while contaminated, by the time you change it damage may have been done.
I have a number of oil analysis for my truck, 544 miles, 2439 miles and 2940 miles. Yes this is 3 oil changes in just under 6000 miles. Reasons for this were numerous, part due to all the engine failures, figured I would have some advanced warning and then decide what to do and I needed to flush all the initial wear metals out of the engine from the original build and break in.
While my driving for the most part is ideal, 80% highway driving, starting the engine and driving between 2-6 hours straight without stopping. Again, almost ideal conditions.
What I found is on my oil samples the Fuel % was typically between 0.5% and 1.0%. On the surface most would say this is fine. BUT lets play some games here. Lets assume 7,500 mile oil change interval which is around what the OLM shows in many cases.
544 mile sample, 0.5%. 7,500/544=13.8 0.5%x13.8 = 6.9%!!! Ok, this one may be a bit unrealistic because the first 8 miles on the vehicle include the final assembly chassis dyno of probably 2 miles or so. Then multiple starts to move the vehicle from the chassis dyno to the initial storage lot. Many more starts getting vehicle on and off transporters/rail cars. Delivered to dealer, need to start and remove from transporter, park in lot for inspection, start engine to move car to storage, start car a few times to get into PDI, back lot, to gas station to fill up before sale, to carwash at time of sale and new owner driving off 50 miles to home! Then mostly in town drives and maybe some highway. So this was not really ideal driving conditions. Probably some rounding error in the 0.5% as well, who knows.
2439 and 2940 mile drives. Oil analysis shows 1%, again, not such a problem, but extrapolate out a bit. 7,500 mile OCI with these 2 distances you end up with 2.5% to 3.0% fuel in the oil. Did I confirm this, no, do not have any interest in ultra long oil drain intervals.
Then lets look at this way. Lets assume for 112,500 of driving, you change the oil every 7,500 miles, this yields 15 oil changes. Lets assume the oil changes cost $100 each, maybe a bit low, but it depends if this is DIY, it would be way cheaper. So this this is $1,500 for oil changes. Now lets cut the OCI in 1/2, you would spend an additional $1,500 in the 112,500 range.
My point of view is you could never even get any internal engine repair performed for $1,500 at a shop, if you DIY, sure you will save on labor, but the point is to drive the car, not disassemble the engine and have a long period of down time. The most likely repair to sneak up on these engines at around 100,000+ miles would likely be problems with the roller lifters and camshaft. Not an easy job, requiring cylinder head removal and so forth. Something I do not want to pay or nor something I want to spend my time doing.
So rather than buying extended Warranties and so forth, I put my money toward maintenance that I typically do myself, so my oil changes are just under $75 with a premium engine oil that feel is worth it.
Everyone has their own ideas and may or may not agree with this philosophy, but as I have stated a number of times, oil is cheaper than steel!