I've got a clear bowl type filter in my avon & I dont think its ever been changed in 4 years ! (I'll check with the guy who looks after it next week)
I assume you are supposed to change the cartridge bit everyso often ?
Every year is recommended. I usually stretch that to 2 years as long as the cartridge doesn't get rusty (a good coating of car wax will delay the onset.)
I was almost stranded about 10 miles south of Kona when a guys Boston Whaler wouldn't start. Couldn't see into the bowl because of a brownish cast to the plastic; turned out to be rust sediment completely filling the bowl. Scraping the gunk out got it running enough to get back to Kona.