When solving a problem in a codebase, you’re not done when the symptoms stop. You’re done when the problem has disappeared and will never come back.
It’s very easy to stop solving a problem when it no longer has any visible symptoms. You’ve fixed the bug, nobody is complaining, and there seem to be other pressing issues. So why continue to do work on it? It’s fine for now, right?
No. Remember that what we care about the most in software is the future. The way that software companies get into unmanageable situations with their codebases is not really handling problems until they are done.
This also explains why some organizations cannot get their tangled codebase back into a good state. They see one problem in the code, they tackle it until nobody’s complaining anymore, and then they move on to tackling the next symptom they see. They don’t put a framework in place to make sure the problem is never coming back. They don’t trace the problem to its source and then make it vanish. Thus their codebase never really becomes “healthy.”
This pattern of failing to fully handle problems is very common. As a result, many developers believe it is impossible for large software projects to stay well-designed–they say, “All software will eventually have to be thrown away and re-written.”