Remaining life assessment is the process of predicting the future operational life of a product based on estimate of life consumed under its life cycle environmental conditions. Remaining life is typically an output of health monitoring and prognostics. In this thesis, a generic 'Health Status Assessment' methodology has been developed, that provides a guideline for conducting a remaining life assessment for electronic hardware already deployed in the field. The methodology presents the assessor with the possible techniques that can be used and the criteria for implementing each technique. A practical application of the new methodology is demonstrated by assessing the remaining life of an electronic circuit card subjected to shock and random vibration loads in its life cycle environment. During life testing, a mechanical support structure on the board was damaged. Analytical and finite element methods were employed to determine and explain the cause of failure.