Never. I value my lungs a lot. My parents smoked heavily. The house stank from it. I recall as a child emptying out ashtrays. Made me gag. There was a time when I had to sit outside at work with smokers. I hated that. They reeked. Their breath. Their clothes. Nicotine- stained fingers. Now non-smokers are in the majority. We do not have to breathe in those toxins. Who wants cancer? Who wants to stink? There are many cessation aids. Some are free through work places even. COPD is a harsh sentence. Ptotect your lungs. Stop smoking.