Struggling a bit with this too. When I bought my 2019 i9, I initially went for 16gb, then reversed myself and sent it back for a 32gb. But I get the impression that I never even come close to fully utilizing that RAM. Here's a chart of my past 30 days of RAM usage:

Most of the time active memory is averaging a bit under 50% utilization when doing my typical stuff (Lightroom, some Safari tabs open, several other apps not actively being used but open in the background, etc.)... so I assume that if I only had 16gb right now, perhaps there would be a bit of a performance hit on occasion, but probably would be mostly unnoticeable.
Even trying to do what for me amounts to a torture test (simultaneously exporting images out of Lightroom, exporting a video out of FCPX, applying a lens blur filter to a huge image in Photoshop, etc.) only bumped up the utilization to about the 55% mark.


Most of the time active memory is averaging a bit under 50% utilization when doing my typical stuff (Lightroom, some Safari tabs open, several other apps not actively being used but open in the background, etc.)... so I assume that if I only had 16gb right now, perhaps there would be a bit of a performance hit on occasion, but probably would be mostly unnoticeable.
Even trying to do what for me amounts to a torture test (simultaneously exporting images out of Lightroom, exporting a video out of FCPX, applying a lens blur filter to a huge image in Photoshop, etc.) only bumped up the utilization to about the 55% mark.
