When you're trying to build a new habit, there are really two ways to go about it.
I subtracted a habit 19 months ago (I gave up drinking). It started as a challenge to see if I could do it for a month. Then I wanted to see if I could do it for two months. And now it's not even a challenge anymore.
Maybe you've done both. If so, which one works best for you? Let me know in the comments.