Due to the increased cost, and time-demanding approach of conventional reliability improvement procedures, the transition towards model-based reliability assessment of power electronics becomes more and more crucial. Although important steps have been taken in this direction, the resulting lifetime prediction is still subject to different assumptions and uncertainties (e.g. mission profile data, modeling errors, lifetime models, etc.). Thus, this paper aims at investigating and quantifying the impact of the mission profile resolution on the reliability estimation of power IGBT modules and DC-link capacitors. For a 10 kW PV application case study, three mission profile sampling rates (1 minute/data, 30 minutes/data, and 60 minutes/data) are considered and benchmarked, with respect to the predicted lifetime of the power electronic components/system. Finally, an uncertainty analysis is performed for the resulting reliability metrics, and some initial guidelines for mission profile resolution selection are provided.