According to the US National Institute on Drug Abuse, the rate of relapse for drug and alcohol abuse as almost 66% within the first twelve months of sobriety. However the longer one stays clean and sober, the more likely one is to remain clean and sober. By the time someone has been sober for 3 years, the rate of relapse drops to 33%. By five years, rate of relapse falls to less than 15%. Source: (http://www.drugabuse.gov/publications/addiction-science/relapse/extended-abstinence-predictive-sustained-recovery)
Anyone who has struggled with drug or alcohol abuse knows that sobriety is hard-won. Even though some moments are easier than others, every second, minute, hour, day, week, month, and year is a victory, and you ought to remind yourself of that accomplishment every now and then; just how long you've been sober, and just how much every second of that time is worth. None of it should be taken for granted.
And sometimes, no matter how much or how little time you've been sober, some moments are harder than others to get through, (a surprise urge to go out can happen to anyone), and this simple little clock can remind you of how far you've come, and how far you can yet go, if only you just hang on to each second of sobriety, if necessary.
Only you can do the work, this is just one tool.