Engine oil OEM Mazda or OEM Audi

I bought a Mazda CX-5 dealer test car with 300 Km's on it back in 2015 when I moved up to Osaka. I drive a LOT and was getting the oil changed roughly every 5000 km's per Mazda's recommendation.

I use Mazda's weight recommendation for my environment, as illustrated in your owners manual. I use 10W-30 and 15W-40 Full-Synthetic oils with zinc additives to stave off carbon deposits.

I don’t drive my car enough to hit any of the reasonable mileage points. I change my oil yearly, roughly around the time it gets inspected. Might be overkill (last year the car moved 2k miles, the year before was 2.4k), but I figure the $80-85 I pay is worth it. My wife’s Q7 will be getting its oil changed every 5k miles. It’s a 3.0T supercharged and they love to eat oil, I’d probably add half the oil back just to make it to 10k.

I do every 5k (2013 S4)

Over here in Germany changing your oil every 3k miles in a normal A4 absolutely tanks your resale value. The only reason to do this frequent oil changes is to hide problems. Personally my car did 30 000km(~20k miles) until 91 000km and then every 15 000km(~10k miles). It's a diesel and almost all longish distance highway trips.

I do 5k/3 months. 3 months usually comes first.

In Canada Audi recommends oil changes ever 15,000km. I always do 10-12,000km because I do city driving. My buddy did every 25,000km on his Mercedes Benz and the thing lasted to 400,000km.

I just change it every 3k as a maintenance think no one told me to. I'm just afraid of messing up my turbo if I waited to long.

2012 3.0tfsi turned out to be a mild hybrid as it burns 1l/5k km.

I encountered something similar when I took my CE Turbo in for service a few weeks ago. The invoice said 0W20 and when I asked the service manual why they used the wrong oil they told me “oh our technicians know what oil to use, ignore that.” Needless to say I have zero confidence that the correct oil was used.