Never smoked tobacco. Like Al, some wacky weed on occasion in HS and uni. My parents both chain-smoked in the house and car until I was 16. I had to suffer through bronchitis once or twice each year and an occasional bout of pneumonia for decades. If you smoke and have kids at home, it can impact their health, too. It did mine.
BTW, I only have personal experience, but once I started taking a liquid Vitamin D caplet daily about ten years ago, the bouts with bronchitis virtually disappeared. So much so that three years ago I stopped taking the daily dose. Now, I only take a Vit D if I feel a cold coming on. The familiar path was cold or flu, advancing to bronchitis, then pneumonia on rare occasions. I always keep some Vit D on hand. Research has shown it boosts the immune system and fights respiratory illnesses. I just use the Costco stuff.