I see some of these recommendations and really have to wonder.

While I take the boat out several times a month, the reality is I rarely use the head... I might use it twice a year. Yes I want everything to work well when I do use it, but how much wear and tear does a joker valve receive when the head is flushed with fresh water and all salt water valves to the head are kept closed.

In my mind I am thinking replace the joker valve every 3 years.

My biggest fear is that valves might seize from lack of use.