The real challenge will be to see how long past your goal you can continue. When I've decided to abstain from specific consumables (nicotine, sugar as an added ingredient, etc), my first goal is 28 days. If I really want to quit, and not just take a break, the next goal marker is at 90 days. If I can surpass 90 days, then I look at the 1 year goal marker. If I can go 1 year, then I'm probably "in the clear", and can possibly tolerate some occassional exceptions to my abstinence. Apparently, after seven years, none of the cells in your body are the same as the ones prior to that seven year period. I'm not sure how true that is, because bones are often dense. Even if it's only true for soft tissue, the "whole new you" may not miss fizzy drinks, and enjoy pure water much more than your old self. Good job, btw. Good health has exponential returns.