Engine coolant, if it is still the factory fitted G13 then it will last for a long time, I have a February 2011 S4 and I bought a coolant test kit which is just a tube of tester/indicator strips, the ph level in my coolant is still "very good" - coolant starts life as being slightly alkaline and as contamination from surfaces affect it, it becomes acidic and that is why it needs replacing - so that means at over 8 years and only 25K miles, my coolant has a long way to go before it requires to be changed, also the freezing point is okay as is the concentration level - these last two should tie in.
I think that initially back in 2011 and maybe longer, plugs + air filter required replacing at 6 years or 60K, I replaced mine at 6 years, the pollen filter should get replaced every 2 years and if you are being tight, just remove it and back vac any dust out of it and check for leaves etc in the ducting. I've chosen to fit a proper pollen filter, ie Frecious from Mann, I don't think that VW Group have caught up with that option yet, original should be Mann filter with carbon impregnated in its incoming air surface.
The initial worry about water pumps in VW Group world was based on VW Group sometimes spec'ing plastic impellors and they could break up or just crack and come loose, I'd doubt if these cars have any issues with impellors, but when you run a car with a cam belt driven water pump, it makes so much sense with the old impellor issues and the fact that if a water pump bearing fails it will wreck the engine/belt and it is easily changed when the cam belt is changed - is what makes replacing the water pump with cam belt a good plan - so that is not an issue with these chain driven engines.
Edit:- AC servicing, it should get treated to a detergent "bomb" every couple of years, if it is still performing ie chilling as it did when new, then I'd not bother going the bother of removing the charge, checking for leaking and recharging - these cars, well at least from MY 2011 onwards, do not decouple the compressor with an electro magnetic clutch, the compressor is a variable displacement type so is always moving fridge gas and oil round the system, just in a lower volume than when actually being demanded to chill the cabin air, so it does not matter if you use or do not use it. Personally I hardly ever need to run the AC chiller but I check its performance in terms of Hi/Lo pressures and vent discharge minimum temperature every summer - again it is still okay, slightly lower running pressures as years go on, maybe this year I'll add in "some" R134A to take it back to where it should be as all these systems do lose some of their fridge gas charge over time across "plastic" O-ring seals and the flexible pipes - its all down to atom sizes - the plastics behaving like a sieve and letting a small weight of gas to escape every year.