Availability is an important characteristic of a repairable system. When the availability of system is low, efforts are needed to improve it. Any improvement in the availability of a system is associated with the requirement of additional effort and cost. Therefore, it is essential to use methods or techniques for availability allocation amongst various components/subsystems of a system with the minimum effort and cost. The concept of importance measures could be used to prioritize the components or subsystems for the availability improvement process. The study shows, it is useful to obtain the availability importance measures value of each component in the system prior to deploying resources towards improving the specific components. With the assistance of importance measures one can identify the components/subsystems that merit additional research and development to improve their availabilities, so that the greatest gain is achieved in the system availability. Each component should be assigned a value and the component with a greater value will have a greater influence on the availability of the system. Generally, the importance of components should be used during the design or evaluation of systems to determine which components or subsystems have the greatest importance for the availability of the system.