<p>Thin-film composite polyamide membranes present a diverse range of aqueous-based applications such as the removal of harmful contaminants and the fractionation of precious resources from water and wastewater. However, their separation performance is typically limited by the permeance–selectivity trade-off. Although the trade-offs related to desalination have been well established, other important membrane-based applications have not been adequately studied. Here we establish various performance plots in terms of permeance–water/solute selectivity and permeance–solute/solute selectivity with respect to the removal or fractionation for diverse separation applications. This will help to bridge the gap between material-level membrane performance and system-level demands for potential applications. We also establish a convenient framework for assessing and benchmarking high-performance membranes in various fields and suggest potential strategies for optimizing membrane properties and/or system performance, which could increase the separation efficiency for membrane applications. This Review provides insightful knowledge and information for researchers and engineers involved in membrane technology.</p>