Forgive me if this isn't the best choice of sections of the forums for my question. Moderators, please move this post if there is a better spot. My question is; what very relevant facts might we be overlooking, in regards to how an oil functions in a car, by making our judgements based almost entirely on UOA's? I'm not talking about fuel mileage, but rather, serious longevity issues like sludge buildup or corrosion of metals by additives in the oil. Personally, I would sacrifice a little more wear on a UOA (not a lot, maybe 50% more, so 10ppm becomes 15ppm) if the oil with the lower wear left a residue on all surfaces that limited heat transfer and sludged the motor, and the higher wearing oil did not. Looking for your thoughts.