Defining the criteria for retiring a model becomes part of turning a proof of concept into a governed production system. Which criterion best fits governance obligations?

Retirement should be driven by actual usage status, because that determines whether the asset still poses live risk and needs active governance, and because the resulting evidence still needs to be kept. The criterion that the model is no longer used, triggering a retirement or archive step that preserves required evidence rather than deleting it, fits governance obligations. The criterion that the original developer has left the organisation, regardless of whether the model is still in use, is incorrect because staffing changes do not determine whether the model is still in use or still needs governance. The criterion that a fixed calendar age applies, regardless of whether the model is still actively used or its evidence is still needed, is incorrect because a model can remain in important use well past an arbitrary age threshold, and retiring it on a fixed schedule risks cutting off a live system. The criterion that a new model with a similar name has been released, regardless of the original model's actual usage status, is incorrect because a similarly named replacement does not confirm the original model has stopped being used. For the exam, tie retirement to actual usage status, not to unrelated organisational or naming events.