@Scott th Ratbag; while you're below fifty years of age, relatively fit-n-healthy the effect of smoking doesn't seem to take much of a toll.
By the time you're in your sixties that's not the case as your teflon coating breaks down - you risk NOT making it into your seventies if you keep smoking as the pressure mounts on your ticker etc! Issues related to poor circulation become increasingly apparent.
Once in your seventies if you keep smoking the story gets ugly, visit to doctors more frequent and what they want to do you more invasive.
My mum was a chain smoker until she turned fifty when her GP told her she'd be dead within two years if she didn't stop [huge BP etc] - she did so and made it to eighty-two, albeit the last fourteen years suffering from pulmonary fibrosis ...
