In self development it seems important to think in long term, and if you do it, you won't find good reasons to smoke. You can read Allen Carr's famous book to quit smoking, I think it has some good points that can help, although you'll have to do the effort for yourself. For me, it was so difficult the first week, and less next months. Now, it's some years since, I don't miss it at all.
About pot, smoking everyday sure affects your productivity and development and you don't need it. Think about the benefits you'll get if you quit.