I still get the sense that many experienced divers (of which I am not one) think that the concern with CO and especially the drive to buy expensive analyzers is an overkill response to a very low likelihood risk. There are lots more commonn ways to get into trouble and the reliance on yet another piece of technology perhaps sends a wrong message that we can be complacent underwater as long as we have bought enough cool stuff. I expect to buy a CO analyzer. But I am still taking the lesson - like from the recent tragedy in Cozumel - that basic buddying skills, using your training, and vigilant self-reliance (not just assuming that your DM will protect you) are required at all times. The toys can be helpful and if you can afford them, why not. But they are not a substitute for the basics. The more experience I get, the more I realize that I have to start being more self-reliant and less reliant on the DM like a newb.
However, in this case basic skills may not be enough to save ones life. CO toxicity can sort of sneak up on you, when you least expect it, rendering you unconcious before anyone can realize it. And if your buddy got his air from the same batch of tanks, or from the same faulty or poorly maintained compressor, then he too may be susceptable to that same poisoning. Basic buddy skills serve a diver, any diver greatly at any level, however they can be rendered moot when both you and your buddy are rendered incapitated oir ill at depth. And sometiems, for al lthe skill in the world, a highly trained, astute buddy may not be enough to help if you go unconscious at depth, loose your reg, and asphyxiate on water. Of course, the incident pit is never that forgiving. A more liklely scenario, is that you fall unconscious, your reg falls away, you draw in water while unconscious. Your buddy finally notices after taking pictures of a moray eel, panics, and rushes you to the surface, blowing past a safety stop or any deco obligation the two of you might have. So now in this worst case scenario, they still have to attempt reviving you, clearing your airways, hopefully getting you on O2, hopefully getting you to medical aid as soon as humanly possible, then getting you and your buddy into a chamber. What could have avoided a near death experience, two bent divers, and a small fortune in hospital costs? a $300 "toy." Most toys are not that effective.
Suggesting that CO analyzers can be viewed as some sort of a nicky-neat toy, takes away from the true purpose of the devices. You should not look at a CO tester and think toy, you should think required tool for my trade or even life support testing. Just as you look at (hopefully) your BC or regulators being life support. If we instill this sort of thinking in new divers, then perhaps they will not view their equipment as toys or as just gear. What you are posting about is a pervasive attitude, amongst recreational divers who look at dive gear as though it is no more than snorkel gear. I think the watering down of a lot of certification programs are a direct cause of this sort of attitude. Just as a Nitrox diver would not dream(Hopefully) of not testing their Oxy content of their tank, we should not think of diving without testing the quality of our air/gas. In this instance, I would much rather decome dependant on this tool, which just may save my life, and is a far cry from becoming dependant on a dive computer for instance. Both devices give me information, however one calculates information I should be able to calculate on my own, whereas the CO checker gives me information I cannot gather otherwise.