Which of the following is a characteristic of periodic maintenance?

Periodic maintenance is characterized by its regular scheduling to ensure that equipment remains in good working condition. This approach involves performing maintenance tasks at predetermined intervals, which helps prevent unexpected breakdowns and extends the life of equipment. By adhering to a routine maintenance schedule, potential issues can be identified and addressed before they lead to failures, ultimately improving reliability and efficiency.

In contrast, the other choices highlight concepts that do not align with the principles of periodic maintenance. For instance, maintenance that occurs only during emergencies is reactive rather than planned, which defeats the purpose of regular check-ups. Similarly, stating that periodic maintenance is not part of a maintenance strategy undermines its integral role in proactive maintenance approaches. Lastly, maintenance exclusively performed at the time of installation would only address initial setup issues but neglect ongoing care and upkeep, making it insufficient for long-term equipment health.