There's a video on YouTube going viral from a dude named Matt D'Avella, a self-described minimalist. He argues in the video that, in order to keep a habit and making sure you're sticking to it, that you never miss MORE THAN 2 days.
Watch the video below:
He notes that it is OKAY to miss a day or two from the habit, such as going to the gym, because we are human and things happen. But, in order to keep the habit from being a former habit, you shouldn't miss more than two days consecutively.
I may try this and see how it goes, for pretty much everything in my life. I'm really good at not missing my Chipotle lunch days, so I should apply it to the gym and see how it goes.