On my Benzes, I change as close to 3,000 as possible. Change my boat engines twice per year, or abouyt every 25 hours. Other currently owned cars around 5000 miles. Hoping for ling life.

But....

When I was around 18, I bought a used 1970 Chevy Impala from an estate with a 350 and a turbo 400 (came like that from the factory!) It was a light green 4 door with a kinda green, kindaq tan plastic interior. I got it for a song and what the heck, it was my beater. A good beater because it only had about 34000 miles on it. Well, this car turned out to last much longer than expected. In fact, I kept it till it had over 200,000 on the odometer. I then sold it to a buddy that gutted it and ran hobby-stock at the local 1/4 mile asphalt roundy-round. I never, ever, not once, changed the oil. Ever. Added about a quart every 5000 miles or so. Never changed the filter. Granted, most of the miles were highway miles going back and forth 50 miles each way to school. My buddy did not change oil either, ran and won a few races, then plowed it into the wall. Who knows how long the engine would have gone.

When I got a different job about 45 miles from home a number of years later, I decided driving a 15 MPG GM Cutlas car was not going to cut it. I saw a brown 1986 Nisaan Sentra, 4 cyl, stick shift, no air, am/fm radio with about 40,000 miles on the clock. This car had brown outside, brown plastic seats, and a brown plastic "carpet". The owner sold it soo cheap, I figured the odo was rolled back. I just needed 40 mpg for a while till I could afford a car I could be seen in. Considered tinting the windows! Anyway, with no intent on keeping the car long, I again drove it to death. Changed a clutch once, a few brake jobs, tires, exhaust, timing belt, etc, but never changed the oil. Again, not ever, not even right after I bought it. At about 190,000 miles, the trans broke and only worked in a couple of gears. It went around 150,000 miles without an oil change, just an occasional top up with the cheapest oil I could buy. I gave it to a neighbor when I moved. Probably still running.

I bought a used Plymouth mini van because my wife said I needed one. I hate the thing. So I want it to go away. So I decided that it was luck with the Sentra and the Impala; I'll just say I change the oil in the van, but don't, and hopefully the thing will simply lock-up. Well, 6 years later, and no oil changes, the WPOS is still going strong. Pulled a camper trailer with it over the rockies with it (mostly in second gear and lotsa rpms), and a 17' drag boat back over the Rockies, again in second gear most of the way. Sucking some oil throught the valve stem seals at idle, but it did that when I bought it. Van had about 90k on her when I had to buy it, now has almost 200k. Still pull the drag boat with it.

So, tell me again why I have to change the oil so often in my current engines? I have hard experience that shows I don't have to change oil. This guy with the 27,000 miles on synthetic that had overheated bearings, maybe it was not oil related? Maybe he ran it low on oil? I've seen many many engines fail because of low oil, but have yet to see one fail from type of oil or length of oil change interval. Or because of an overheating condition in the cooling system, causing a breakdown of oil. As for severe service, cheap dino oil is what I used in my beaters. And I think I have severely overloaded the minivan. I hate that van but it sure has been good to me. A lot cheaper to run than a Benz!