This Note explores the determinants of key attributes of a training program for Individual Ready Reserve (IRR) members. It examines relationships among time since separation, skill retention, task characteristics, and different forms of training. It analyzes the relevant academic and military literature on skill retention and training needs, and proposes a research agenda and a decision framework designed to provide information and structure for IRR training program decisions. The authors recommend that decision frameworks for IRR training take into account the usefulness of other mobilization assets, the time and resources available at mobilization for IRR training, the skills that are critical to mobilization, and cost concerns. This decision framework must be supported by further information on skill retention in the IRR, training needs of the IRR, costs of refresher training, and the willingness of the IRR to train.