Maintenance is work performed to keep a system or equipment operating as intended. Maintenance procedures might be conducted to repair damage to the system, or to prevent potential failures, such as replacement of worn parts.
Understanding maintenance requirements is probably the easiest part of this process called inspection, testing and maintenance. Simply put, maintenance must be performed in accordance with the equipment manufacturer's recommendations. All manufacturers publish maintenance requirements. They are the instructions.
For many components, these are part of the UL listing or FM approval of the component. Management needs to keep a copy of these.