I have had my 75hp 4 stroke Mercury for almost three years now and thought it was a good time to change all my anodes. What do people think about when changing their anodes, probably just the ones you can see right?? Dont forget about the anodes that are in the engine block. Mine has three in the engine block and they looked terrible when I took them out. Not sure how just freshwater effects them but all I can tell you is that if your in any salt or brackish water you better order some quick if you dont know about them. Just in case people say you should of used salt away, well I do use it everytime I go out but over three years of use it was definitely time to change them. It was about $30 for all three of the anodes and about $15 for the gaskets. I also changed the ones down by the trim tab and under the hydraulic ram, and changed the thermostat which wasn't in good shape either. Its just about time for people to start getting their boats ready for spring fishing so I thought I would post this. Have a happy and safe boating season to all.