My truck has run Schaeffers since about 15,000 miles, it has 111,000 now, with 12,000 to 13,000 mile drain intervals.
my last sample shows wear metals at:
copper 2
iron 32
chromium 1
aluminum 4
lead 5
I also have several stationary pump engines with up to 9000 hrs that run 24/7 all summer and a tractor at 7800 hrs on this oil with 500 hr changes and similar sample #s. My opinion is that the stationary engines will last at least 25% longer than when I was running a "house brand" oil from my distributor at 250 hr changes, when I check the valve lash it needs much less adjustment and the engines are much cleaner inside than the last engines. I never ran a premium oil such as delo or rotela so I cant compare to them.
Jared