I was smoking 30-35 a day until 1991 when I packed in...In 1995, I developed an allergy to cigarette smoke..Ironic really.
My Mum who has smoked for most of her life since her teens, gave up about ten years ago but has just recently been diagnosed with lung cancer!
Glad I gave them up and just feel sorry for those who can't find a way to do the same. Believe me I know how hard it is.
Best wishes.