Cruising, you're going to be anchored out most of the time. Conditions aren't always marina flat. With the constant motion of the boats, stuff begins to grow above the usual marina waterline. I put my top of bottom paint 4"-6" above the flat condition water line to deal with the green scum that creeps up the topside.

Inevitably, stuff you can't live without gets loaded on board. Before you kinow it, your down on your lines. Not a bad idea to periodically go through every locker on the boat and make a decision whether you really need the stuff that's in there.