With a focus on its intersection with the expertise literature, a number of conclusions arise from the present review of the skill/knowledge decay and retention literature. First, decay is more a matter of interference rather than simply the forgetting of information and processes through the passage of time. Second, decay is highly dependent on task and situational factors. Third, decay on complex tasks appears to be smaller than that observed for simple tasks. Fourth, retention is generally stronger with more practice, elaborative rehearsal, and greater mastery—expertise—of the task. Fifth, although related, retention, reacquisition, and transfer are meaningfully distinct. Sixth, there is very limited empirical research that integrates the study of expertise in the context of skill acquisition with the study of decay, adaptable performance, and enhancing retention (or mitigating loss) in complex real-world performance domains. Intersecting these rich yet separate literatures would be of great theoretical and practical value and warrants future research attention.