Just wondering what others do. My engine is a Yanmar 3GMF with a Racor for the primary. The tank is clean and I use a fuel polisher to clean the fuel before it goes in. The vacuum gauge needle sits between 2-3 where it's been all year. There's about 110 hours on my current filters. It's not a big deal to change them and I usually do it after every season when I change the oil but is it really neccessary to do it that often? I think my manual suggests a change of the engine mounted filter every 500 hours.