you need another option-"it runs but I rarely touch it".
I used to run it all the time with the supra. typically every minute the boat was running. it seemed to help vaporlock on the hot days and really doesn't hurt anything.

current boat automagically runs for 5 minutes every time the key is cycled so I don't do anything when launching and cruising, but when surfing, I turn it on for the entire session. again due to the load the engine is under and the low speeds. it's cheap insurance to draw some of the heat out.