My 2016 Model S' aircon set to 11 was barely seeping out of the vents, took it in for service. Tesla Richmond charged me $266 to replace my very clogged cabin air filters.
The DIY Youtube videos looked intimidating, I passed. But, if I "should" be replacing the filters every year or two, I need to suck it up and do it myself from now on.
I believe this is the first time the filters were replaced.
Replacing the HEPA filter was never mentioned.