I’ve seen it recommended to replace it every year. Mine has failed now every 5 to 10 years. When replacing it, be sure to take the pump totally off the boat by removing the hoses. You will find pieces of the old impeller lodged in the housing. I don’t think it would be good for these to go into the water jacket of the engine. When the impeller fails the engine will not sound right. It will be louder because of the absence of the water. And the temperature gage will go up quickly. Shut it off quickly.