In USA, German cars are treated as semi-luxury vehicles (and the manufacturers often encourage this by only offering higher end configurations in USA), with parts and service being far more expensive than they should be. :/
Alongside an outdated culture in the US to change oil very often:
It used to be normal to change the oil every 3,000 miles, but with modern lubricants most engines today have recommended oil change intervals of 5,000 to 7,500 miles. Moreover, if your car's engine requires full-synthetic motor oil, it might go as far as 15,000 miles between services!
"might go as far" (with a qualifier to limit the applicability) vs manufacturer warrants it will go at least that far, bordering on misleading. Synthetic motor oil? same price as the rest here.
European cars tend to cluster their oil intervals at the higher end 10,000km or 20,000km and 1-2 years between oil change, while some manufacturers like Subaru say every 6 months!
Some mechanics do profess the benefits of regular oil change. Even if the are in the servicing industry, the point they make is neither the interval nor the miles driven is entirely precise. It depends on the condition of the oil itself. When it's time, it's time.
Cadogan Video: [url]https://www.youtube.com/watch?v=TuiVdQWGmWI[/url]
Cadogan is usually immaculately accurate on automotive topics, but actually stumbles a little on this one. Servicing periods do have a tolerance/limit to them, and its not usually not the publicly stated service interval (which he says is a hard absolute maximum limit). Like I point out in the quote above, a little emotional sleight of hand pushes people to replace their oil more frequently than the manufacturer actually recommends. Going on into "well its actually more flexible and depends on the specific history/operation of the vehicle" is trying to take a bet both ways.
Time limits: largely humidity absorption in these situations, but also material outgassing/absorption. Both dependent on temperature. Some manufacturers vary these by region where the car is sold.
Distance limits: accumulation of byproducts/wear/contamination. Set by worst warrantable conditions (go worse and they say it was abuse of the vehicle, example: stop-start batteries in taxis/courier vehicles).
Cadogan discusses a stop/start short distance car driven many times a day as far more damaged over distance travelled than a grand cruiser only doing the occasional country drive, but to keep warranties safe the oil is usually still mandated replacement on schedule. Some newer cars are accumulating "wear" on the oil at differing rates for different conditions and bring up the oil change indicator at a different rate. DPFs on Subaru diesels are very picky about contamination (again mentioned in the video) but they are still an accumulated damage, so its only a statistical prolonging of life by sticking to the set schedule. Its not guaranteed to get a certain life, everything in modern automotive is engineered to last sufficiently long for warranty/consumer protection. Many approximations and guesses are involved, its not a hard limit.
Plenty of vehicles (treated carefully/well) will be seeing little to no degradation by going over the set time limits, but when testing for the physical limits is more expensive than replacement, things just get replaced. Heavy vehicles with huge volumes of oil are economic to test for life extension, small cars not so much (good luck getting appropriate test limits for a light vehicle out of the manufacturer).
Also much of the limits are set by the manufacturer before the car is released (rarely do they update them after sale), which for new designs might have very little historic data to back it up. Once a design has been out in the wild for a decade the mechanics start to see patterns of what was either too lax or too restrictive. I know a specialist car mechanic who adjusts the schedules away from the factory figures, some go longer, some go shorter. But only once they are out of manufacturer warranty. The same engine model, with the same line item service parts can see different schedules in later facelifts or models of car (again up or down). Do I watch those things and change the service intervals based on the new data, absolutely! Will the manufacturer suggest you change? No.
* blimey, the forum aggressively embeds youtube links!