Final answer:
The owner-user Inspector is responsible for inspecting and certifying both repairs and alterations to boilers and pressure vessels, not just routine maintenance.
Step-by-step explanation:
The owner-user Inspector is responsible for ensuring that all repairs and alterations to boilers and pressure vessels follow applicable codes and standards. In this scenario, the Inspector's responsibilities include the inspection and certification of both repairs and alterations. Routine maintenance, on the other hand, does not typically require an Inspector's certification unless it involves work that could affect the pressure retaining integrity of the vessel.