Classic engineering economic theory was developed to furnish the analyst with a tool to compare alternatives on the basis of life-cycle cost (LCC). However, tools used to apply theory to transportation focus on new construction projects with relatively long service lives. These tools do not accurately model the economic aspects of short-lived alternatives such as those that pavement managers must evaluate when seeking the most cost-effective pavement preservation treatment. The field of pavement preservation seeks to "keep good roads good," and hence pavement preservation treatments are applied to extend the functional service life of the underlying pavement. No significant research has been done to quantify the actual service lives of the pavement preservation treatments themselves nor has a model been furnished to analyze their LCCs. The paper addresses those two gaps in the pavement economics body of knowledge by proposing a methodology for using field test data to quantify the service lives of pavement preservation treatments for both asphalt and concrete pavements. In addition, the paper concludes that an LCC model based on equivalent uniform annual cost, rather than net present value, specifically addresses the relatively short-term nature of pavement preservation treatments and allows the engineer to better relate treatment LCC output to annual maintenance budgets.