Inventory management is a critical balancing act for companies, serving as both an operational necessity and a significant financial burden. This study focuses on optimizing spare parts inventory management in a cosmetics factory, addressing the substantial costs associated with poor practices such as stockouts and overstocking. Our research implements a novel management policy to enhance spare parts inventory control. The methodology comprises three key phases: 1. Classification of spare parts based on criticality: We developed a multi-criteria system considering factors such as unit price, lead time, and consumption rate to categorize spare parts effectively. 2. Performance criteria calculation: We evaluated the cosmetics company's current inventory management practices using key performance indicators (KPIs) such as average inventory levels, turnover rates, and coverage ratios.3. Application of the Wilson Economic Order Quantity (EOQ) model: Based on our classification and performance analysis, we employed the Wilson model to determine optimal order quantities for different spare part categories. This integrated approach allowed us to validate our study's effectiveness and provide data-driven recommendations for inventory optimization. By combining criticality-based classification with quantitative modeling, our research offers a comprehensive framework for managing spare parts inventory in the cosmetics industry.