Importance measures have been widely used as meaningful decision-aiding indicators in reliability engineering, risk management and maintenance optimization. However, few importance measures integrates the actual condition (working states or degradation levels) of components that dynamically evolves with time. This work develops a novel time-dependent importance measure defined as the capacity of a component (or group of components) to improve, when it is replaced, the system residual life. The proposed $I{M}_{\mathrm{MRL}}$ measure can help to better prioritize a component or group of components regarding to its improvement ability in the system life time while considering the actual conditions of all components of the system. The originality and complementarity of the proposed measure when compared to existing importance measures is also investigated. The proposed importance measure is then extended to integrate the economic dimension of the maintenance decision, through the maintenance costs, the benefit gained by the maintenance operations and as well as the economic dependence between components. It is finally shown how the proposed $I{M}_{\mathrm{MRL}}$ measure and its extension can “optimally” suggest a component or a group of several components for preventive maintenance decision-making, based on both the technical criterion (residual life of the system) and the economic aspects (benefit and costs). The use and the advantages of the proposed importance measure and its extension are illustrated on a four-component system.

重要性度量已被广泛用作可靠性工程、风险管理和维护优化中有意义的决策辅助指标。然而，很少有重要性度量能够整合随时间动态变化的组件的实际状况（工作状态或退化水平）。这项工作开发了一种新的与时间相关的重要性度量，定义为一个组件（或一组组件）在更换时提高系统剩余寿命的能力。拟议的$\mathrm{一世}{米}_{\mathrm{最大残留限量}}$在考虑系统所有组件的实际情况的同时，度量可以帮助更好地优先考虑一个组件或一组组件在系统生命周期中的改进能力。还研究了与现有重要性措施相比所提议措施的独创性和互补性。然后，通过维护成本、维护操作获得的收益以及组件之间的经济依赖性，将提议的重要性度量扩展到集成维护决策的经济维度。最终显示了提议的方式$\mathrm{一世}{米}_{\mathrm{最大残留限量}}$基于技术标准（系统的剩余寿命）和经济方面（收益和成本），措施及其扩展可以“最佳地”建议用于预防性维护决策的一个组件或一组多个组件。在四分量系统上说明了所提出的重要性度量及其扩展的用途和优点。