Obsolescence issues are one of the main costs in thelife-cycle of sus-tainment-dominated systems, those that require support for many decades.Obsolescence not only occurs when a system element becomes no longer availa-ble due to manufacturing updates or production interruption. It also includes the deterioration ofthe system or component capacity to operate as intended, since it is no longer suitable to fulfil its function, even if it still operates and can be man-ufactured and supported. As such, italso impacts on the“-ilities” (reliability, functionality, etc. ...) whichcan be even traced to legislation changes, for in-stance, the anti-pollution legislation updates for automotive.Obsolescence has so far been mainly addressed from a reactive point of view. Around 70% of the total product cost is committed asa result of decisions in the early design stages. Late changes induce delays in the life-cycle plan and large increases in cost due to re-design and rework. Knowing the impact of the con-ceptual design phase on life-cycle cost, this paper intends to present a model-based systems engineering approach to proactively assess obsolescence risks.The approach uses obsolescence considerations as constraints during the early design phases, to allow the identification of components potentially at risk of obsolescence. Presenting designers with thisinformation allows them to improvethe design, by makingit robust and resilient, or to accept the risk and develop an obsolescence mitigation plan. Itwill be illustrated with an example from the automotive industry.