I'm not one of those that unnecessarily worries about my engine wearing away.
I follow the manufacturer's recommendations in the Owner's Manual for both interval and oil type, which has me wondering why we have all those stupid "what oil" threads on forums...can't people read? I have yet to have an oil related engine failure in over 40 years of vehicle ownership.
My VW manual specifies oil changes every 15K kilometers.
By the way, a co-worker who owns a BMW 330 Ci since new changed his oil every 22K to 24K kilometers. He now has well over 300K kilometers and amazingly, the engine is fine. He would get the old oil tested in our labs and it was still fine.
You see there's a huge difference again, the intervals for the Jetta here are 35000 to 50000 km, and you've just said yours are 15000!!!
The temperature extremes have something to do with it I am sure. We go from -30C to +30C where I am. Also the oil available in Europe is not necessarily available here. They have different standards.
VW Canada (and VW NA) is likely covering their butt with respect to warranty and we all know that everything revolves around the almighty buck. Some unscrupulous dealers have set that oil change interval via VCDS to 10,000 kilometers just to increase business. I verified mine and sure enough it was. I reset it to the VW Canada recommended oil change interval of 15,000 kilometers using my VCDS. Mind you, I might do it sooner to avoid having to do it mid-winter outside in the driveway.
Someone has a 35K or 50K kilometer oil change interval? Who exactly? That I would like to see in the Owner's Manual or on-line maintenance schedule. Wow!
Most European manufactures now advise anywhere between 18,000 and 30,000 mile oil change intervals. My car recently had it's first service with 10700 miles, I assumed they would change the oil. But it's 18,000 miles or once every two years, whichever occurs first. I think the 30,000 mile interval applies to people doing that mileage in a year, sales reps and people who travel on the highway a lot.
Also the oil available in Europe is not necessarily available here. They have different standards.
For one thing, the US court ruling that using 'synthetic' on the label to mean near synthetic levels of properties and performance was alright wouldn't apply to Europe. It technically shouldn't apply to Canada, but it generally is how it goes in the US is how goes in Canada in these matters.
So nearly all the 'synthetic' oil on the store shelves here is really just a synthetic blend. There are a few, but they are pricy or hard to get. Ironically, as the term is used now, the Castrol Syntec, the product that lead to this ruling, 0w40 is German made and a true 100% group IV synthetic.
So the manufacturers don't have an oil change interval here as long as in Europe in order to CYA in case that near synthetic performance isn't enough, in part.
The big part is likely the dealer associations. Besides Tesla, no car maker sells direct to the public. They have to go through independent dealers. These dealers do a lot of business in service. So they likely pushed to keep the interval shorter.
I read that Mobil 1 and Valvoline High Performance are or at least were fully synthetic.
Was that the case then and still now?
Having used Mobil 1 in my last car from the 1st inspection at 1000 kilometers for 15 years, all I can say was there were no scuffs on the approach side of the cam lobes the last I checked at about 189,000 kilometers.