We're liveaboards, so the seacocks remain open almost all the time, but if we're leaving the boat for more than a day or so, or it is being hauled out, then all the seacocks get closed. There's not so many of them (2 each for 2 toilets, 1 for watermaker
, 1 for salt water
washdown, 2 each for 2 engines, 1 for genset, 1 for A/C). I made little laminated signs "Seacocks closed" that we stick in the appropriate places on the instrument panel/breaker panel to remind us (or someone working on the boat) of the status of each.