How do I check maintainability?

Short explanation:

Maintainability means another developer can understand and safely change the code without discovering hidden dependencies. Clear responsibilities, names and contracts reduce the chance that a small change breaks unrelated behavior. Abstraction helps when it removes a real duplication or dependency, not merely when it adds more classes.

Key points:

• Prefer clear names, small responsibilities and explicit dependencies.

• Remove duplicated business rules and unexplained constants.

• Add types where they clarify real inputs and outputs; avoid unnecessary abstraction.

• Prefer a small explicit function over a generic framework if only one straightforward behavior is required.

Interview point:

• Explain how your suggested refactor makes a likely change or test easier, rather than arguing only from personal style.