This chapter explores the challenges and perspectives in the study of cementitious materials, particularly focusing on sustainable and low-carbon concretes. It highlights the importance of understanding the microstructure, micromechanical properties, and chemical composition of interfacial transition zones (ITZs) and paste matrix in these materials. The chapter discusses limitations in current nano-characterization techniques, emphasizing the need for accurate and reliable sample preparation methods. Future directions include the development of non-destructive and automated surface preparation techniques, as well as the integration of in-situ and 3D imaging methods to better capture the complex microstructures of cementitious materials. The chapter also explores strategies for improving the efficiency of micro/nanomechanical testing of ITZs, suggesting the use of polished aggregates and advanced imaging techniques to overcome heterogeneity challenges. Overall, the chapter underscores the necessity for more precise and comprehensive characterization methods to enhance the understanding and application of sustainable cementitious materials.