Yup, if the chiller still seems to be chilling the cabin well enough, then I tend to leave it alone.
changed or even hoovering out the cabin filter at every (home) service is a good idea, I tend to buy Mann Frecious versions of these filters from whoever is selling them cheapest. Mahle now market their version maybe quite cheaply from ECP, they have their own name for the one that is same idea as Frecious - just check the full description on the ECP website, it should include “fungicide”, basically there tends to be 3 options for these filters:- basic, carbon coated and then fungicide- which also has the properties of the carbon version. It really depends on your personal allergies etc
I’ve tended to buy one of these “bombs” from ECP and run that through the system (see instructions, tends to be, with all windows closed, the the AC on recirculate and place the “bomb” in the rear seat well, and set it off, close doors after exiting the car - leave like this for ?? minutes, open car doors, switch off, remove now empty “bomb” - job done! But, I tend to do this while replacing the cabin filter, so, remove old filter, cover up the empty filter housing, run the cleaning routine using the “bomb”, after that fit the new filter.
The other details of the alternative to Mann is a Mahle ie Knecht which is similar their trade name for that is CareMetix.