I think the Napa 1553 that Huskee listed is a 30 micron filter.
Maybe I should of got a 1551 or 1552 which are 10 and 20 micron, respectively.
Oh well, we’ll see if I use them in another decade.
think you're just fine w/a 20-30 micron filter. although tsc (in my area) no longer carries the huskee line, they have the original 25 micron spec filter for huskee.
as far as the op's question, think a filter only replacement every 200-300 hrs (probably more) would be in order assuming the correct hyd oil is used to top off w/each change. think it's mainly a moisture/ condensation issue for most homeowners, probably commercial too.
in fact between filter changes (when cold) one could just back off the existing filter w/o removing it & purge any settled moisture or contaminants each season say a qt or so of fluid. just a thought.