Selective laser sintering (SLS) has great potential for producing 3D components, particularly those with complex geometries and customized designs. In SLS printing, only a small amount of the powder is sintered into parts during each build, while the rest remains unused but preheated. Discarding this unsintered material is both costly and wasteful. Reusing polymer powder helps reduce material costs and enhances the sustainability of the process. However, powder reuse affects the polymer, impacting its processability and the quality of printed products. Previous studies have shown that excessive reuse of powder significantly alters e.g. the mechanical properties, and visual appearance of printed parts as well as the flowability of polymer powder during printing. There is still a lack of practical methods to easily determine, under real process conditions, when a powder has aged beyond usability. In this study, we aim to improve raw material efficiency, reduce waste, and enhance material recycling by evaluating analytical techniques using real process samples of PA12. Our goal is to examine powder samples obtained from actual SLS process and provide companies with information on the effectiveness of different analysis methods in obtaining reliable data on material aging and reusability.