Opportunistic Maintenance (OM) is one of the key approaches for optimizing maintenance operations in Closed-Loop Supply Chains (CLSC), which leverages the repair and recovery of spare parts to reduce costs and improve reliability. In this paper, a new OM model is proposed that, in addition to classical factors such as component age and economic and structural dependencies, incorporates spare-part material type, technician skill level, and environmental conditions into maintenance decision-making. The material of spare parts directly affects their failure rate and service life, while technician skill enhances repair quality and post-repair lifetime. Moreover, environmental conditions such as temperature and humidity alter the degradation rate of components. Preliminary results and conceptual analyses indicate that the proposed model can reduce costs, improve the overall performance of the closed-loop supply chain, and enhance the reliability of repaired components.