I’m not sure how much truth there is to it, but I heard that smoking raises estrogen levels. For that reason alone, you should limit how much you do it (this is assuming you’re on this site for the right reasons), if not quit altogether (and assuming it’s true, which I can’t confirm either way).
After saying that, I partake myself (a lot less than I used to) and most of my friends do, too. I understand first-hand how easy it is to get attached to it just as well as I understand how much fun it can make the simplest daily tasks and events.
My advice is to stay strong-willed and not let it start to take over certain (or all) areas of your life (like your diet, maybe?). I know plenty of people who do it and lead very successful lives in terms of careers, health, etc. and I also know plenty of people who justify doing it every chance they get and let it affect their lives and are continually in denial about it and think it’s not a problem. Don’t be like the second group I described and I think you’ll be fine.
So the take-home message? Always make sure your will is stronger than your weed. If it isn’t, then stop doing it until you can learn how to control yourself better. Know your limitations and don’t put yourself in a position to fail, put yourself in a position to succeed. If that means you have to let it go, then do what you have to for the sake of yourself. Can’t think of any better reason to do or not do something.