My Mother smoked for 50 years,pretty heavily too!
3 years ago when she had to go into the hospital for her heart surgery the Doctor told her she would be better off in the long run if she tried to quit!
I never thought she would even try it never mind do it...but she did. Came out of hospital and (to my knowledge) has never smoked again since. Some woman my Ma when she puts her mind to it

And she was 71 years old!