jigen, my father in law is the same kind of guy, oil changes only, no oil level checks in between whatsoever.
He has a 2000 Toyota Echo, all fluids are original, oil changes only, at 200,000KM (120k miles) it's still going, although it drives like c!rap.
The funny thing is, he says that this car is the most reliable of all the cars he had in the past, I just laugh as 200,000 km is not a lot at all, but he thinks it is.