I smoked 2 and 1/2 packs of Marlboro a day back when i gambled at pool on a daily basis, 365 days a year. One day I couldn't breathe, so I went to the doctor. He laughed (honest) and said I always had at least half my lungs filled with smoke at all times. Said he never saw a more perfect candidate for cancer. That laughing hyena makde me so nervous I increased my smoking output by about a pack a day for a couple of weeks. But actually, I have him to thank in part for finally breaking the habit in 1972.
They say your body replaces every cell in seven years. I don't know if that's a fact, but it's a comforting thought after what I put my body through.
Today I only smoke other people's smoke, which I sincerely hope is not as bad as some say, since I spend lots of time in smoky casinos and pool rooms.