Thanks for not yelling Marty,
There was a study done on engine degredation and frequency of oil changes. Seems that new motor oil caused damage for the first 500-1000 miles until "broken in", something to do with molecular changes due to heat and friction - I am not an engineer.
Changing the filter was THE best thing one could do to prolong engine life. Unfortunately, the modern engine does not allow one to change the filter without dumping the oil. VW/Audi has a 24 month filter, which I don't trust to live that long. My 1975 B30F engine has a filter high up on the block which allows for the filter to be changed, but that car still gets petroleum oil so I won't have to worry about leaking engine seals.
My daughter does a lot of cold engine driving (to/from school daily, 4 miles round trip) and I change her oil every 2 months. That is to take care of any water trapped in the oil. I guess I could just take her car out once a week and run it for an hour to get it nice and hot, but that is almost the same cost as an oil change.
Not everyone's driving styles and conditions are the same, so when the oil/filter gets changed varies with the car and the driving conditions. Unless you live in a very cold climate and make short trips, changing the oil every 3,000 miles makes no sense to me.

Klaus
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(1975 164, 1995 854T, 1998 V70R)