Thanks Agin Guys! How often do y'all suggest it be changed?
That's a good question. I would say every year, to be on the safe side.
However, I had my boat for almost three years ---- with regular use, say, at least once every three weeks on average ---- and when I went to change my impeller, the old one was near perfect. So they can definitely last almost three years, if that gives any perspective on the matter.