Traditionally, expertise theories have focused on skills acquisition with little regard for the domain or contextual factors affecting expertise development and retention. Because the development, retention, and recruiting of individuals with expertise is critical to organizational success, it is essential that HRD professionals understand the influence of such factors on individuals, and how to address these changes and the redevelopment of expertise. This article proposes a Model of Expertise Redevelopment (MER) illustrating the redevelopment of expertise in three states--dependence, independence, and transcendence. Connected through continuous development, the states are influenced by three territories: content, constituency, and environment. Although the model can explain the initial development of expertise, it is the model's representation of the impact of change on existing expertise that makes it unique. It also contributes to a broader theoretical foundation for research on this topic and calls for further investigation of the interconnectedness among the three states and the territories influencing expertise redevelopment. (Contains 1 figure.)