What do I think? As I sit here sucking away on yet another Camel non-filter? Been smoking these things for years. Yes, it limits you, some more than others. At 40 I don't have the same endurance I had at 30, but who does? I can still dive past the length of my floatline, 15M, which is why I went to a 20M floatline yesterday, even though all the larger fish I've shot lately have been about 30' or shallower.
For anybody that's thinking of starting smoking, don't do it. Health concerns aside, figure out how much money you would spend on cigarettes, a pack a day over the next ten years, put it all in a pile and burn it. That's what you would be doing with that money anyway. Or, better yet, send that money to me and I'll send you a nice thankyou card. Which is a lot more of a return than you would get from the cigarettes.
P.S.-I promise not to spent the money on smokes. Instead I'll use it to support my Riffe habit (having a few more around here certainly wouldn't hurt).