Different service lifetimes: Transient, Scoped, Singleton?

Short answer: Lifetime Description Use Case Example Transient New instance every time Lightweight stateless services Scoped One instance per request Database context, UoW Singleto One instance for the app's lifetime Logging, Config access

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.