C4I systems have evolved rapidly over the last few decades, and the cost of keeping these products up-to-date on new and in-service U.S. Navy ships is high due to configuration, integration, testing, and other challenges. Looking across a specific set of completed C4I upgrades, the authors found evidence of cost improvement, a high level of variability in costs, and a trend toward overestimating the installation-labor costs of certain upgrades.