This Note identifies some major sources of variability in the Air Force's budget forecasts for depot-level component repair. These forecasts are estimates of the amount of money the depot system will need to repair components that cannot be repaired at base-level maintenance facilities or that the depot repairs as part of an overhaul or repair of a higher assembly or end item, such as an airplane or missile. The findings indicate that current requirements and capability assessments systems do not explicitly consider parameter variabilities and forecasting uncertainties. They suggest that these uncertainties will always be present in some form and that the Services should enhance management adaptation during budget execution and explicitly account for these adaptations during the requirements process. The findings also indicate that the Services do not use consistent operational goals when developing requirements and executing the budget. The author proposes that future research focus on developing requirements methods and budget execution systems that account for potential management adaptations, support tradeoffs between the repair and procurement of spares, and consistently reflect the operational priorities of the Services.