[est31]

TBH this issue exists in many larger codebases that don't take separations of concerns seriously. Solution: take it seriously. That's harder than it sounds and depending on the problem domain is next to impossible, you should still try it.

[Matthias247]

Absolutely true, the issue exists in many code-bases and organizations. And even trying to keep things decoupled will only help so much. A 10+ year old codebase which is mostly driven by new feature development will very often have accumulated so much cruft and workarounds that trying to make and further modifications is rather likely to break something else.