As a new diver, and new to the board, I find this an interesting question. I was going to ask about how often you are required to have an Octo to dive in a charter or resort situation, I never imagined it would be such and issue. In my training which was a semester long university course taught by an old school dive master we practiced buddy breathing every time we were in the pool, twice a week for and hour for twelve weeks, so twenty four hours in the pool. Were didnt start on gas right away but probably four weeks in, so sixteen hours of pool time with buddy breathing exercises every day. The rigs we had to get certified in had no Octo and I remember being told the octo was necessary as in a teaching capacity, but an option for the average guy. We did drills in the pool where instructors would come from behind you and your buddy and mess up our gear, i.e. turn off tanks, tear of masks, inflate BCs, etc. often you would both find yourself with a failure. Working out the problem together was the object and buddy breathing was often part of the solution. I had my tank shutdown without my knowledge while helping my buddy through another scenario so know what it feels like to have the airflow stop. While these were controlled scenarios in an 80 degree pool with unlimited vis they built a lot of confidence and when I set myself up I did not get an octo. I have very little dive experience to date, but nobody has said anything to me when I show up to dive without it. It is my understanding that if my second stage fails it will fail open so having an additional second stage for myself makes no sense to me. If I am out of air or the first stage fails another second stage does me no good. This sport is all about risk management, on deep dives and/or in an overhead environment I see it as being more important, but in forty feet of water off the beach? Not as much.
