I have read on this forum in the past about people having trouble with them. Something about the paper element swelling possibly due to water if I recall. Whatever the reason, I would want to be able to easily check them for water/debris and general condition regularly (more often than annually). If they are located in the cockpit, this is difficult and messy. For what it's worth, I think I've solved this by installing Andair gascolators in the wing roots. They provide filtering and water collection just outside the tank. They are easily sumped before flight, and any crud is stopped before getting to any fuel system components. Also, in the unlikely event that there's so much crud that a filter is somewhat "restricted", I can always switch to the other tank which has it's own filter. Just my personal preference. I think the first tankfull of fuel is likely to wash the most debris into the fuel system. Bevan