FAQ 4.12 What happens if the domain analysis is incorrect?

It costs money.

Once a domain analysis mistake has been discovered, randomly patching the code makes matters worse. Instead of patching code, fix the domain analysis error. Unfortunately, fixing domain analysis errors often breaks existing code.

Even though changing existing code is expensive, it is often far more expensive to continue building the software based on a faulty domain analysis. Domain analysis errors usually make software brittle.

That's why it has been said that domain-analysis errors are ten times more costly to fix than programming errors. If you must make changes, sooner is often much cheaper than later.