I routinly go 10K - 15K miles between oil changes in my truck. It is a diesel and hold 4 gallons of oil, so oil temperature is much more stable, and there is much more oil there for the additives to be in, but I have not had a consumption problem yet. I loose more oil to all the leaks that Ford designed into the oil delivery system than the truck burns. I do have a by-pass filter that filters really small particles out of the oil, don't remember, but I think it filters to like 2-3 microns. This is just a bypass filter, so not much oil goes thru it and it goes really slow. On big truck, it is not uncommon for them to NEVEr change the oil. They will just drain a little out change the filter and top off the level with new oil to replenish the additive package.

Either way, I don't feel that oil wears out, but it just gets loaded with junk. The stock filter just can't filter the small stuff out, if you were to put a filter on the engine that actually did filter the small stuff out, it would either be as big as the engine or not flow enough oil.

For my TCH, I just plan to have the dealer do the changes at the recomended 5,000 marks with the 0w20 oil and whatever filter they decide to put on there. If they recomended 10,000 miles between changes, I would go 10,000 miles.