The State of California Fleet Administration ran extensive testing a few decades ago and came to the conclusion the filters should stay for 2 OCI's and oil should be changed at 6,000 miles. They administer some 25,000+ vehicles, so that's a big enough test to validate their results (no one-offs).
There are also some technical papers derived from recent studies that say that oil makes AW compounds as it ages in an engine. Compounds that are unique to that engine, environment (outside air temps, etc), local fuel, and drivers habits like hard acceleration, or not. These compounds are very beneficial to engine life and better overall lubrication.http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/4049815/1/Diesel_Piston_Ring_and_Liner_W
The oil you are using can readily go 10,000 miles. You are changing it before then, so the the detergent levels are always high and so is the TBN. One way to counter part of this fresh oil is to leave the filter and it's contents and only change it after the second OCI so that there is always some residual "used" oil in the system.
I have moved to this scenario after doing the do diligence and reading the papers. Others are moving in this direction too.
If the car does not consume oil, does not have a mechanical failure, and does not darken the oil prematurely (like first week), it's safe to say the the filter is not catching much. It is certainly not "full" by the change interval.
The biggest concern for wear is Fe particles in the system. Add a magnetic drain plug and catch those there. the filter can go longer. So can the oil as long as it's that oil (good) or an equivalent.
I agree with getting in, under and around the car every 6 months as visual inspection is important. But modern oils are taking us away from the short changes we grew up with ... Follow the book, but don't do unnecessary work or become overly compulsive about clean. Then engine wants what it wants and as long as it's OK (running well) just do what's prudent ...