Here is my ralliart, with 13,000km old fluid and filter getting changed:

And here is another one that is 30,000km old:

These don't have some crappy auto box that you can just let go for 50,000km. They are a German engineered precision box which requires the cleanest conditions to operate properly. And for gods sake never take it to the dealer for an SST service. I do the full service including filter and fluid for $390, so the dealer is just ripping you off because he can. Plus they never change the internal filter, nor do they drain the cooler.
And I have based my recommendations on the 10+ SST that I service regularly. You'd be amazed what a fluid change does to the driveability...