Galvanic anodes have been used to provide various levels of corrosion protection to reinforced concrete structures for many years. Some installations have met expectations and others have not performed as desired. Failures have been associated with lack of understanding of the performance of anodes with time. Long-term monitoring of galvanic anodes has allowed detailed analysis of their performance and aided in the understanding of the way performance diminishes with time and how temperature affects current delivery. The aging effect of the anode is described by an Aging Factor which was found to be specific to each anode type. Knowledge of the Aging Factor and the mean annual temperature has permitted performance expectations and duration of protection to be defined prior to final design. Successful designs are designs which meet the specified performance expectations for the design service life and are based on the actual performance of the specified galvanic anode in the service environment. The temperature and corrosivity of the environment must be considered. Long-term galvanic anode performance data has been used to validate the proposed design approach.