Hey BITOGERS, I had a quick question regarding the thought processes of major manufacturers in extending the recommended oil change intervals. -- Why don't major manufacturers just make the oil capacity larger and include some kind of multiple filter/ bypass/ magnets to extend oil change intervals? From what we see from the likes of Mobil 1, Amsoil etc... Oils should be able to handle 25,000 miles without much drama? Does it all boil down to cost or am I missing something? Maybe an additive you add after 15,000 miles to "rejuvenate" the oils?