Commercial-grade plastic encapsulated semiconductor devices are now widely used in space and military equipment for their cost-per-performance and availability advantages over military type ceramic parts. However, many equipment manufacturers still perceive risks in their deployment, and conduct expensive and time-consuming screening and qualification programs to mitigate the potential risks associated with their use. This paper discusses the limitations of the screening and qualification approach currently employed by space equipment manufacturers to assess the long-term reliability of commercially-available plastic encapsulated semiconductor devices (PEDs) in deep space missions. In addition, the paper presents the value of the high temperature operating life (HTOL) data published by manufacturers of PEDs for mitigating the risks associated with the use of such devices in long-duration space applications, where steady-state temperature is the significant stress parameter.