I use the 10 micron Yamaha filters, I get 100 hrs out of them or more, I believe Yamaha says change them every 100 hrs. If you use the boat enough and gas never sits you should not have issues unless you get a bad load of fuel somewhere. If your boat sits you might need to change them more often, especially if it sat for more then 2-3 months. The filter should be changed atleast 1 time a year at a minimum. I always carry a spare pair for my boat, quick and easy tyo change on the water if they have issues and your going to sue it at some point when it needs replacement anyways, might as well carry the spares on board, could salvage a trip rather then ruin it and make for a bad day on the water.
If your having issues with the filters, upgrade to a racor, I wish I had, it is on my list of upgrades for the future for sure. Racor now has a 2 micron filter as well, the finer the filtration the better off your engine is, bad part is you might go through more filters or need to drain the bowl more, but whatever keeps your engine from seeing bad fuel is worth the money.