FWIW.
The only batteries I disconnect are the ones in the boat and RV because those on-board chargers will fry the batteries over the course of a few months. I put a blade-type disconect on one post, leaving circuit open when on the Battery Tender.
Everything else (ATVs, M/Cs, tractor, lawn mower, seldom-used-farm-truck) has a pigtail on the battery, no disconnect, and always plugged into Batter Tender brand maintainers whenever not being used. Not a problem that most of them have clocks or other low current draws.
