From Refactoring: Improving the Design of Existing Code:

In many ways, refactoring is like exercise and eating a proper diet. Many of us know that we ought to exercise more and eat a more balanced diet. Some of us live in cultures that highly encourage these habits. Some of us can get by for a while without practicing these good habits, even without visible effects. We can always make excuses, but we are only fooling ourselves if we continue to ignore good behavior.