Since its introduction, the study of artifact design has shed new light on the nature of variability in prehistoric technological organization. Few ethnoarchaeological studies exist exploring the interrelationships between subsistence risk, the costs of technological failures, and the design of artifacts. This ethnoarchaeological study investigates these relationships in a transhumant agro-pastoral case study from the southwestern Bolivian altiplano. Three aspects of tool design are explored to document variability in design characteristics between and within assemblages from agricultural and pastoral residences. These design features consist of the reliability of raw materials used in tool manufacture, the reliability of joints used in compound tools, and the maintainability of tools in case of partial or total failure. While time-budgeting constraints differ at pastoral and agricultural residences, the costs of production shortfalls are equally severe. In response, artifacts from both residences are designed to be highly reliable. However, depending on the likelihood of tool failure, artifacts are designed with different raw material and joint reliability to either minimize tool failure or maximize maintainability. Multiple backups and replacement components are accumulated and maintained to reduce subsistence risk caused by the failure of artifacts with high potential failure rates or low maintainability.