With 140k on my '90 Ive changed the oil about 5 times in as many years.
Never changed a belt.
Never changed or cleaned the air filter.
Added coolant twice (because of the problem Ill mention below).
Never changed the tranny fluid.
I rebuilt the motor from the crank bearings out last year because I blew the HG, but we came to the conclusion that the previous owner (teenaged girl, 0% mechanically inclined) overheated and warped the head, because when we miced the head it came out wacky, so we had the head shaved (which actually probably gave me like .05 more CR

)
Anywho while we were in there, not one part showed any signs of wear. 3/4 crank bearings looked literally brand new. One had a bit of scoring that was undetectable by touch, which is pretty good for a 140k mile original part (we replaced them anyway since we had new ones and they are considered "wear parts" to be replaced when rebuilding, like gaskets).
But like I said, 140k mile all original bits and the engine was in pristine shape (aside, of cousre, from the damage that was done when I blew the HG).
And I drive my car HARD.
I especially drove it hard when I first got it. Burnouts, neutral drops, I did everything that I know better about now that Im not such a n00b.