Do you define an interface for every public class in your domain model? Pros and Cons? [closed]

Question

Do you implement an interface for every public class in your domain model? Pros and Cons?

Update: If Repositories interfaces and domain model classes are defined in separate assemblies, wouldn't there be circular dependency if we do not define interfaces for every domain class.

Answer 1

No.

Cons.

1. Noise code.
2. More to write.
3. YAGNI.

Answer 2

You should define interfaces for dependencies between layers, not for every class. So your Service layer should depend on a repository interface, and your presentation layer should depend on a service interface. Past that, there aren't many hard and fast rules, other then use them where it makes sense.

Common sense is a good part of any good design.