Since its introduction in the late 1960s, six-port technology has served as a valuable tool for determining the amplitude and phase of microwave signals. This purely passive technology offers adaptability at high frequencies, extending its applicability up to the terahertz (THz) level. However, its historical limitation in sensitivity has hindered its competitiveness against traditional vector network analyzers. Despite this drawback, six-port technology possesses exceptional phase-resolution capabilities, which render it suitable for addressing emergent applications. This work outlines the evolution of six-port technology, highlighting its strengths and potential for innovative solutions in microwave nondestructive testing and beyond.