For an Interstellar Probe mission to succeed it must operate successfully for 50 years. Although some missions have successfully operated for time approximating 50 years (Voyager at 43 years, for example) none have had such a requirement. To better understand the implications of this 50 year requirement, the Interstellar Probe study initiated a “lifetime study” task. The study team focuses on three areas: spacecraft reliability, maintenance of the necessary ground infrastructure, and organizing a team that will be able to operate the mission for multiple generations of engineers and scientists. The Lifetime Study team will provide an overview of the work to date, some initial conclusions and the work planned to provide guidance for those who plan this mission and for other long duration missions now being considered.