I actually did this last October — I didn’t drink, was vegetarian and committed to writing everyday. While it was a few different habits, it was a good test bed to see how it felt. It was even more liberating to know it is for a set period of time. After that time was up, it felt as if I had accomplished something already and then it was my choice to keep it up or commit to redo it again in the future. It’s definitely easier on our psyche.