I’ve seen companies rapidly collapse because they couldn’t adapt their code base to current platforms or new requirements. As long as nothing changes and you don’t have too many bugs, your code can look like crap under the surface without issues. It’s the day you can’t sell your product without a UI that works on a phone and you have to change every single method to make the change, or you fail to implement the new tax rules correctly even after 18 months of all hands on deck, it matters.

Then it doesn’t have be that bad to have business impact. What does your customer say when the new feature that was promised in one month takes eight months to deliver, or your CFO say when it will take 15 years of licensing fees from that customer to pay those 24 man months to get the features working?