Hi Clint,
I wouldn't replace them if the housings are in good shape. Mine were fine but I replaced the barbed thru-hulls with seacocks and backing blocks (I don't like thru-hulls you can't close). Personally, I also favor metal fittings below the WL but have not heard of plastic ones failing. BTW - I noticed quite a bit of corrosion in the baffle of my mixing elbow (raw water cooled). Not a good scenario if that corrodes through. Anyone had one of those fail?
Seth
