Code Reusability:?

Short answer: The common structure of the algorithm is defined in the abstract class, so subclasses don't have to repeat the same steps. Only the details of specific steps need to be implemented in each subclass.

Real-world example (ShopNest)

Use a GoF pattern in ShopNest only when it removes duplication or makes a change safer—explain the problem it solves in the interview.

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.