Check this out
1,000,000 MILES
In this website they lobby for selling their filters, but as long as your existing filter in the engine is not teared appart it will function the same way as theirs. Its just paper stopping some small metal particles, totally no other function. Question rises; if the truck has passed 1 milion miles without oil change did the filter upgraded the oil or did it just stop the metal particles if the filter is not comprising of something other than paper!?
According to some facts i have a feeling that the oil becomes better the older it gets. (Just like wine). I know you'll laugh at this but there is small secret somewhere.
Anyway my test is ongoing, yesterday i checked (fingerfeeling) the oil viscousity immediately after I turned the engine off after a 60 Miles drive. The oil was perfect with a lot of viscousity.