divinh
Contributor
I get the sense that some guides feel more comfortable when they're the ones doing the final valve checks because they feel they're responsible (or an incident had caused them to be this way). On a recent trip, I brought my own gear, set it up and did checks myself, even though it was full service. I usually turn off, depressurize, and only turn back on before the dive. Some guides would just ask me about opening the air and some felt the need to twist the valve themselves. It didn't matter either way to me, because before splashing, I still do an air check again with multiple breaths, just to be sure it's not just partially open or closed.