I started smoking when I was 11 years old. I became a scuba Instructor when I was 23, I continued smoking because I could still hold my breath and play underwater Hockey every week. I then married a non smoker. She was Ok with my smoking till we tied the knot. She laid down the law, I would have to brush my teeth before I could kiss her. That was a hassle and after a year of being married, on Dec 1983, I smoked my last cigarette on New Years Eve and haven't smoked since. The biggest negative thing that I went through was weight gain. I have a younger brother who started smoking 5 years after I did, and did not quit till 2012. My brother is a Marine Biologist , and was a hands on research scientist in the Philippines, sop he dove a lot. In 2016 at a dinner he stood up during the meal and said he was having a hard time breathing. I treated thought it was a heart attack, so the ambulance arrives and he gets taken to the ER. They said it wasn't a heart attack it was a pneumothorax. After his battery of tests they found three more "Blebs". He yad to go through "VAT" video-assisted thoracoscopic surgery, to deal with the other blebs. He can't dive anymore. It doesn't bother him and much as it would have bothered me. He dove for work and he was tired of doing it. I don't think he enjoyed it as much as I did. So I have seen the "Pain in the neck" results of quitting smoking and I have seen the effects of not quitting early enough. I don't dive as much anymore, but my foot is still in the door because I moved in the Hyperbaric Medicine world in 2007.