I am running my WVO through a triple filtering setup I made in my garage. First I run the WVO from the cubbies through a Baja Funnel Fuel filter when I first put it into my 55 gallon drum - so I know there is no water and there are no particles larger than 74 microns in my drum. Then I pump via a rotary fuel pump through a primary fuel filter that cuts down to 10 microns, then through a secondary filter that cuts down to 2 microns - a Racor 75100MAX. The oil coming out of my system looks like apple juice - and since the in-line filter in my GreaseCar WVO system is a 10 micron filter, I assume (yes, I know what happens when we assume!
) that I should never plug a fuel filter again!
As far as miles per filter, I don't really know. Just to be safe, I'm changing the filters when I change my engine oil.