Dalek

This is in no way meant to imply that your Beast is "doing pushups in the parking lot", getting buff while you sit on a folding chair eating doughnuts, getting out of shape and weaker (whether in real life or in front of a computer), but just as you will inevitably re-organize around your new non-drinking/using mandate, so will your Beast re-organize in response to your Big Plan. The Beast is a survival drive, a living, feeling thing, and no living thing wants to die, so it has no choice but to do this. Expect a few curve-balls, knuckle-balls, and slider-balls from your Beast.

So, set your confidence for lifetime abstinence arbitrarily at 100%, and recognize all self-doubt as AV, as your Beast talking. Treat it as any other AV, and you'll do fine.