On the pickup and Tuktuk, i only used the combined oilbath filter, a final safety filter could be a good idea, but i don’t have soot in my system so i don’t bother.
In the short run small engines, i just use foam
I can put any filter ( original paper, swimmingpool, or dirtbike filters) in line.
Its up to the machine i use and the purpose i am using said machine/engine
Since i never use the long term before maintenance schedule, it works just fine for me.