What is the definition of service life?

The definition of service life is best represented by the time between installation and removal. Service life refers to the length of time during which an item, system, or piece of equipment can be effectively used before it is retired from service or replaced. This encompasses all operational use, including maintenance and any downtime, but it specifically focuses on the usability of the asset from the moment it is installed until it is no longer functional or is taken out of service.

The other options highlight important concepts but do not fully encapsulate the service life. The period from delivery to disposal describes a broader timeline that includes the entire lifecycle of the product rather than just its effective use phase. The duration of product warranty relates to the manufacturer's commitment to service or replacement under specific conditions but does not indicate how long the product can be actively used. Likewise, the interval for scheduled maintenance pertains to prescribed upkeep periods and does not define the overall service life of the equipment.