Congrats on kicking the smoking habit! Yeah, if you read BJ Fogg's book Tiny Habits, he describes how we really choose to perform behaviors. The harder they are, the less likely we are to do them, even if we want to do them a lot. So something like smoking, which is hella addictive (my dad stopped smoking in the 1940s, and says the craving still hits sometimes... that's 70+ years later!), you have to make super difficult -- throwing out all your cigarettes, not hanging out with people who smoke, etc. in order for you not to do it. For good behaviors, making them as easy as possible to do helps make them habits, to get over those days when your motivation to do them is low. So 30 days is the average to make a habit stick, but you can start a new habit in as little as 1 day or take as long as a year. It's all about how easy it is to do, and how much you want to do it.