While most people focus on the coffee machine, one shouldn’t forget to take care of the water source when away for a long time.
I typically drain my Osmio Zero as if I were shipping it (emptying the internal reservoir and the cartridges) and clean the water tank before going away, and run at least 4 litres of water through it once back. I guess it’s also possible make this coincide with filter replacement, but that is not always cost effective if one goes away relatively often.