This chapter proposes a novel hybrid method for RUL prediction that addresses the challenges of modeling the effects of both external shocks and internal degradation, focusing on the dependency between these factors. By combining degradation models with field data, the method assesses RUL under the influence of system degradation and external shocks. A dependency factor is introduced to account for the interaction between degradation stages and shock intensity, improving system failure prediction. Comprehensive uncertainty analysis is performed, considering random degradation, unpredictable shocks, and the dynamic evolution of system degradation. The method is validated through numerical simulations on a hydraulic control system, demonstrating its robustness and accuracy in handling complex dependency modeling and uncertainty. The results show that the proposed approach effectively predicts the RUL of the hydraulic control system, while also identifying the vulnerability of its subsystems.