Which item generally requires continual restocking based on supply lines?

Expendable items are those that are consumed or depleted through normal use and need to be continually restocked to ensure they are available when required. This includes items such as oxygen masks, survival kits, and other supplies that can be used once and then discarded. Because these items are essential for safety and operational readiness, they must be maintained at sufficient levels through regular resupply efforts.

In contrast, nonexpendable items are durable goods that are not consumed and typically remain in inventory for longer periods, repair parts are specific components that can be used as needed to fix or maintain equipment, and equipment maintenance refers to the actions taken to preserve the functionality of equipment rather than the provisioning of supplies. Therefore, it's the nature of expendable items to require regular and ongoing restocking based on usage and supply availability.