How does SRP improve maintainability?

Short answer: SRP improves maintainability by: Reducing complexity – Classes are smaller and easier to understand. Easier testing – Each class can be tested in isolation. Better separation of concerns – Business logic, data access, and infrastructure code are kept apart. Lower risk of bugs – Changes in one responsibility don’t affect others. Ultimately, it leads to more modular, flexible, and robust code.

Real-world example (ShopNest)

Open/Closed in ShopNest: add a new payment method by adding a class, not by editing a giant switch in CheckoutService.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.