The implementation of additive manufacturing (AM) for spare parts has gained substantial attention in recent years. This article examines how AM affects the management of spare parts inventory. Specifically, an approximate one-for-one inventory model for spare parts is used to analyze how inventory-related benefits can be derived from reductions in holding cost and production lead time. Key results indicate that (1) a reduction in holding cost has more impact on reducing the stock-out probability when the average demand rate for spare parts is low and (2) lead time reduction may negatively affect the stock-out probability. The framework is applied to a published case study to underscore the impacts of AM implementation on inventory strategies. Potential applications and current shortcomings are also discussed.