That kind of explains it a bit then. Higher emission standards and higher refined fuels in europe are a few reasons why we dont need to change our oil that often. Oh and my mistake, I meant 30,000 km which is 19,000 miles. Most modern cars younger than 4 years have service intervals at this mileage, but I think most car manufacturers recomend an oil change at least once a year anyway.
Exactly. So back to my inital point, if there's an Audi in the US that does 60,000 a year, it might have 20 oil changes, where as an Audi in Europe doing the same miles might have 2 a year. So the same car doing the same miles might have much higher running costs etc.
I drove boats for a living for about 15 years, the manufacturer's recommended oil change inverval was 100 engine hours for most diesel engines in private yachts. Some with large oil tanks went signifcantly longer but again it was normally a function of the engine's internal oil capacity multiplied by the external oil tank's number of additional crank case capacities times 100 hours. For example, one boat had a 5 US gallon crank case capacity and a 20 gallon external oil tank, it's change interval was 500 hours.
Aircraft ICE engines are also based upon engine hours, most are between 100 and 200 hours of cruise power, but high performance turbo charged engines can be as low as 50 hours between oil changes.
For what it is worth, the 3,000 mile oil change used by most auto manufacturers up until about 20 years ago was based upon an estimated average speed of 30 mph for 100 engine hours. Then later when there was the 3,000 around town interval and 5,000 mile freeway interval it was still based upon 100 hours at 50 mph average freeway speeds. Yes, some engines are good to go with much higher mileage between changes, especially considering the better additives and some synthetics having drastically improved qualities from traditional oils, but thank you very much, I'll still change my oil around the 100 engine hour mark for my cars, it is frankly cheap engine insurance and once in a while I find a problem early that prevents me from having to pay for a full rebuild when I can replace a small sub assembly or part.
If you choose to go with more than 7,500 mile intervals I strongly suggest that you regularly use a Spectrometric Oil Analysis Program to monitor your oil and engine for wear and issues. I have no idea about the cost in Europe but in the US there are several available that charge around $35 to $50 per test to check your oil for engine wear, oil breakdown, dilution (from fuel getting past the rings), and other issues. I tend to run a SOAP test on my cars after 100,000 miles or so every year or two even though I change my oil at the 100 hour mark, again, it is cheap insurance IMHO over costly repairs.