Services are perishable in two regards:

• Service-relevant resources, processes, and systems are assigned for service delivery during a specific period in time. If the service consumer does not request and consume the service during this period, the related resources may go unused. From the perspective of the service provider, this is a lost business opportunity if no other use for those resources is available. Examples: A hairdresser serves another client. An empty seat on an airplane cannot be filled after departure.
• When the service has been completely rendered to the consumer, this particular service irreversibly vanishes. Example: a passenger has been transported to the destination.

The service provider must deliver the service at the exact time of service consumption. The service is not manifested in a physical object that is independent of the provider. The service consumer is also inseparable from service delivery. Examples: The service consumer must sit in the hairdresser's chair, or in the airplane seat. Correspondingly, the hairdresser or the pilot must be in the shop or plane, respectively, to deliver the service.Each service is unique. It can never be exactly repeated as the time, location, circumstances, conditions, current configurations and/or assigned resources are different for the next delivery, even if the same service is requested by the consumer. Many services are regarded as heterogeneous and are typically modified for each service-consumer or for each service-context.[2] Example: The taxi service which transports the service consumer from home to work is different from the taxi service which transports the same service consumer from work to home – another point in time, the other direction, possibly another route, probably another taxi-driver and cab. Another and more common term for this is heterogeneity.