At the end of the year, we start to define new year’s resolutions, and them —if kept— lead to positive changes in our lives; these goals propel us forward and are worth pursuing.

If we want to reach these goals, we can follow the ‘Rule of Four.’ Simply put, it takes four good things to overcome one bad thing. It means we don’t have to set up unrealistic scenarios when we start a self-improvement plan. We’re likely to fall short of our expectations from time to time —and that’s okay. It’s more important to get back on the horse than to give up completely.

Usually, we give up on our goals very quickly after the first time we slip up. This is the ‘what-the-hell’ effect, and it describes a vicious cascade of counter-productive behavior the moment we break our commitment.

The key is to break the cycle with this rule: Instead of demanding perfection and despairing when we fail, we could aim to stick to our regime at least four days out of five. While some goals—like quitting smoking—might require a cold-turkey approach with no wiggle room—most goalsetters benefit by following a virtue-to-vice ratio of 4 to 1.

Write down the days where you are on track with your goals, and compare them with the failed ones, so you can check if you are following The Rule of Four.

Summing-up: The Rule of Four is a powerful goal-setting concept because it recognizes a reality of human nature: most of us overestimate the amount of willpower it takes to stick to a goal. We also fail to consider the demoralizing effect of a small setback. One negative event or setback has much more impact than a positive one—at work, in our personal lives, and in the goals we set for ourselves. Break the cycle by making sure your good days outweigh the bad.