All:
Agreed that we should do what we are comfortable with in the long run.
This being said, it is very true that both oil and engine technology have grown in leaps and bounds over the last 20 years. Having been around vehicles that see extended idling time as well as extreme driving throughout their lives, the big thing is to use a good quality oil and fillter. I would never run "just what is on sale" unless the vehicle in question burns oil like a sieve, or is a beater.
As long as you follow the intervals in the owners manual, your engine should live a long and happy life. I like the Mobil 1 because of the cold winters we have here in Ohio. Motorcraft makes a very nice semi-synthetic oil for a good price.
I drive around 10k miles yearly, and was doing my oil /filter every 4mo/4k. If BMW,Corvette, and Mercedes, etc say you can run good oil as long as your monitor tells you, then it is ok.
Oil and filters are cheaper than a motor, but think of the mods or beer, etc you can buy with the money saved. The overall effect on the environment is positive as well.
FWIW......YMMV........Don
