Eight months on oil. (Went 2 months longer than recommendation because only drove about 400 miles in last 2 months.) Mix of high-speed highway, dusty 4WD off-road rock crawling and stop/go city miles. I suppose it is so worn out there are no more wear metals to be had. Fram Extra Guard oil filter was not changed at beginning interval of the oil sampled here. (Only change every other time.)