We have a 2004 248LS that will stay in the water; just got it a couple months ago. Following what several of our friends do, we actually have a diver for the bottom, but about every two months we'll float around and do the one step wax/cleaner on the hull. The topsides gets a similar treatment about the same time. The SoCal sun beats down pretty hard so we plan to try to stay ahead of it. We have a bow cover and cockpit cover so the inside stays pretty clean, but every couple months we plan to use the same one step cleaner/wax after a good rinse. The vinyl we'll probably clean once a season and use the conditioner on it.
