Filter for the A8

Often you forget to change a filter in the car in time or you don't know that there is one.
For example, in gas conversion. There are two gas filters. ==References== Liquid phase and one in the gas phase.
Both should be changed after maybe 25,000km.
When the petrol filter changed, for example, clean petrol came out on one side and a dark grey liquid on the other side, which was contaminated gasoline.

So the following filters should be changed as required:
Oil filter
Gasoline filters
Gas filter (liquid phase)
Gas filter (gas phase)
Air filter (K&N permanent filter?)
Interior filters