We demonstrate how resource costs arising in a given year can be influenced by Age Factors. The model allows you to set the Age Factor for Maintenance Cost, which could be used to reflect a deferred Maintenance Cost. The maintenance of new equipment could be under warranty for a period after installation (e.g., 2 years), and only after the warranty had expired would the operator need to pay for a maintenance contract. The results relate the Maintenance Cost to the Installed Units of the resource.