All true if you do it yourself but the vast majority of divers don't, remember this is life support gear and no one but specially trained techs should touch it, otherwise you will die.
I am sure you know I am kidding but there plenty of divers who believe that or just don't want to do the work for whatever reason. I see tech doubles in our shop for service all the time. Those folks will have to pay for 2 vips instead of one and they also have to pay for a dissambly/assembly charge. Even if vips and hydros are free, you will spend nearly (if not more) double the cost of a single tank when purhcasing the equipment and that does not take into consideration a new set of bands, all for little more or more likely less gas. For most divers it makes more sence to spend the same amount on 2- 80s instead of 2- 40s, a manifold and bands. They are cute and fun to dive but from a cost perspective a total waste.
