Mine has always been attached to the first stage except when I had to change the short hose, never had an issue.I separate it when storing my gear after a dive. I don't like threading and unthreading something all the time. Then again it's not like I thread and untread for fun. Comes from my shooting habits with suppressors. Threading and unthreading will inevitably wear out threads at least on a rifle. That's why all my cans get QD mounts.