Final answer:
Fire extinguishers and Class D extinguishing agents should be inspected regularly, with fire extinguishers being inspected monthly and Class D agents being inspected every six months.
Step-by-step explanation:
Fire extinguishers and Class D extinguishing agents should be inspected regularly to ensure they are in proper working condition.
Fire extinguishers should be inspected at least once a month to check for any visible damage, ensure the pressure is within the recommended range, and verify that the safety pin and tamper seal are intact.
Class D extinguishing agents, which are specifically designed for combating fires involving combustible metals, should be inspected every six months to guarantee their effectiveness.