A4's don't seem to be that fragile. Mine is still absolutely fine after nearly 5 1/2 years as it was a really early, Nov 2015 car. All I'm doing is the regular services and replacing what wears out; last week front discs and pads. 61 500 miles and going strong.
If you are doing much less than 16 000 - 18 000 it isn't worth it. I'm fairly marginal at 16 000, mostly on fast A roads. Less than that and stuck in slow traffic would not be good for the engine or the DPF