Programs are rewritten and modified far more often than they are ever created. That means most of the time developers must change and modify existing code either written by someone else or written by you sometime in the past. Since you may be writing code that you or someone else will eventually modify in the future, you need to make sure you organize your code to make it easy to understand.
While every developer has their own programming style and no two programmers will write the exact same code, programming involves ...