It's really hard to avoid broken window syndrome when developing: legacy code from ages might not be up to standards of today and often developers use it as excuse when developing new features.

By introducing some code style enforecement tools we can get rid of 'there should be a space there' code reviews, while static analysis tools can help us not only locate some possible bugs in existing code but help us avoid new ones as well.

But it's not all in the toolset, we need to build some traits in our teams to understand the importance of good code quality and keeping it on the level as we go.