In what way is it going to save you later...especially with a raw water cooled boat where you aren't worried about antifreeze in the oil?
I can somewhat see the value in an engine in a truck or auto but doing them on boats kinda doesn't make sense to me especially if you are a person who puts so little hours on an engine that you are skipping seasons to change the oil.
Just a believer in doing preventative maintenance when it is needed, and not doing it when it isn't. (also, I have access to free/cheap oil tests!)
2 consistent tests told me that the oil had a lot of life left in it, wear metals were good, and it was within grade. That is the same as changing your car's oil at 3000 miles but yet the manual says 6000+. You are just flushing money based on myths and wivetales, not science. (lots of people still do exactly that for vehicles, for the sole reason that is how their dad, and their dad's dad did it. Not one bit of it based on science (aka oil testing)
One other thing to consider... You might be doing damage in the startup after your oil change, unless you pre-fill your filter AND run the starter with the ignition disabled until you get oil pressure. (which very, very few people do.) I have a lot of experience in a specific high performance car environment, and there was a very distinct trend of people losing bearings under 200 miles after an oil change.
2 tests can tell you a trend that can save you later though. I usually run 2 seasons on oil now, have for quite a few years. (and of course, tests tell you far more about your engine and how it is running/wearing.)
