My current daily driver is a 98 Ford Contour SVT that I have owned since new. It now has 205,000 miles on it and still runs as well or better than it did when it was new.
Up until about 190,000 miles I changed the oil every 3,000 miles, nearly all of that with Mobil 5W30 dino. The oil level on the dipstick never dropped between changes.
At about 190,000 I switched to Mobil 1 and 5,000 mile oil change intervals. I found that it consumed oil, but not until after 3,000 miles. The dipstick level is still full at 3,000 miles, but drop after that. I need to add a quart after 3,000 miles (about 3,500 to 4,000) before changing oil. Actually it may not be consuming any, as there is a slight oil leak from the front crank seal and the oil pan gasket.
I tried Valvoline high milage full synthetic and it is also dropping at the same pattern.
When I get around to it, I will repair the leaks. I'm still thinking of going back to the dino oil and 3,000 mile intervals. The newest Mobil 5000 looks really interesting.
My intention is to get to 300,000 miles and then see if I still like the car (I probably will) and determine if I like it well enough to provide any major things it may need by then. I'm sure it will need paint, but maybe not much more. I would almost like an excuse to put a 3.0 Duratec engine in it, or maybe even a 3.5 Duratec when Ford starts making them. But then, one of the reasons for not making any modifications on it yet is to retain it's dependability.
If you agressively maintain a car, you can make it last longer than you probably want to keep it.
The car before it was a 1971 Mercury Tracer LTS (that's the one with the high performance Mazda DOHC engine). It had 170,000 miles on it when it met it's untimely death at the side of the road against a guard rail. It also had the oil changed every 3,000 miles, mostly with Mobil 5W30 dino oil and also consumed no oil between changes.
The family van was finally retired at 260,00 miles when it was donated to charity. It was a 1984 Ford Econoline Club Wagon. It was in service with our family for 19 years. I finally got tired of it and tired of fixing it. The EGR spacer plate below the carb had blow out so that exhaust was mixing with intake all the time. It was a company vehicle that I took delivery on when it was new. When I left that company, I bought it from the lease company. I did most nearly all of the maintenance and repairs on it, including replacing the water pump three times and the timing chain once. I followed a 5,000 mile oil change interval with it because that is how it started life under the direction of the leasing company. Most of that was with Castrol dino. In it's younger days it usually had 20W50 since it had a lot of heavy use with a heavy load in hot weather. After I bought it and it had lighter use, I found it started better with 10W40 and still used Castrol. When I replaced the timing chain at 175,000 miles, I also replaces the leaking valve cover gaskets. I was shocked at the quantity of sludge. It may not have been Castrol's fault, but I have avoided their oil ever since. I know that everyone's oil has improved a lot since then, but a 5,000 mile oil change interval should not have been a problem.