Smoking
I lost both my maternal grandfather and his daughter, my mother, because of uncontrollable smoking habits. They both struggled right up to the end to draw breath because the cigarettes had destroyed their lungs; it's a crappy way to die. I realize not every smoker will meet this same fate, because of genetics, etc., but enough do to state it as fact.
Do whatever you can to encourage her to quit. If it takes hypnosis, nicotene gum, whatever, make an effort to help (not "make" or force) her to quit. The only person who can make her quit is her. She has to be the one to want to make the change.
Sorry for the lecture, but it's a topic I feel strongly about.