I change my engine and genset filter when they start rusting.
I change my primary filters when the vacuum gauge tells me to.
I change my polishing filter also when a vacuum gauge tells me to and this is the one where that actually happens. I end up replacing my primary filters now and then because I want to clean the bowl, replace the O-ring etc. so I pop in the new filter.
In short: it all comes down to how dirty your fuel is, if the filters corrode or break down in any way etc.
The 100h or 200h rules for fuel filters are weird but will
work. They will also result in good filters thrown away now and then and also in filters not getting changed when they should be. The vacuum gauge is the way.