When should you choose unique_ptr, shared_ptr, or a non-owning pointer in C++?

Use std::unique_ptr for exclusive dynamic ownership and transfer ownership explicitly with move semantics. Use std::shared_ptr only when independently managed shared ownership is actually required. A raw pointer or reference can express non-owning access when lifetime is guaranteed elsewhere. shared_ptr does not make the pointed-to object’s operations thread-safe, and strong reference cycles can prevent destruction; weak_ptr can break suitable cycles. Prefer values and standard containers when dynamic ownership is unnecessary. The type should make who destroys the resource understandable to a reviewer.