I was in a dealer where a guy was getting his 4th oil change at 20 k miles, and he had only had the car for 6 months, I was shocked, and said you are not harsh city driving (aka sitting in traffic) why are you getting it changed that early?
he said "because the dealer said I had to"
I replied that sitting in traffic for an hour driving to and from work on a trip covering 20 miles is not the same as driving 70 miles on the highway.
He was like "oh yeah" 10k miles or every 6 months is just fine, (I say 6 months because of the possibility of unburnt fuel entering the oil during the winter, is higher and and if you are not driving 10k miles in 6 months the oil could not be getting hot enough to evaporate off the moisture and fuel in the oil.) the service manager was like, but I want the extra revenue.
I would almost bet money they are just changing the filter and topping off the oil on the 5 k and charging for an entire oilchange...
I changed the conventional oil in my 85 golf every ~5000 miles, or more(broke collage student at the time), and the car never burned any oil, even at 190k miles (amazing for a gas car)
My grandfather who ran a CONOCO station had a loyal customer who came in every 3000 miles and got a fresh filter and a quart of oil, he had never drained the oil, until my uncle did an oil change one day, the owner was pissed he had 40k miles on the car and the oil plug had never been out. he managed to back out of the price of the oil change.
A properly maintained and functioning engine will not contaminate the oil, so why change it? the trouble is most people do not properly maintain or pay attention to their cars.
A business owner selling used cars said that about 3/4 of the local people never change their oil, they just buy a new used car every 3-4 years because their engine fails.