Reliability is a critical performance metric for power semiconductor switches and power electronic systems. Yet guidance on how to test and quantify that reliability is fragmented in the existing literature, particularly with the rapid adoption of wide-bandgap (WBG) devices and novel packaging technologies. This review brings guidance on what designers, reliability engineers, and researchers need to know about power cycling testing (PCT). We provide three major contents: first, introducing how new materials and packaging shift dominant failure mechanisms; second, comparing the main PCT standards joint electron device engineering council (JEDEC), automotive electronics council (AEC), international electrotechnical commission (IEC), and automotive qualification guideline (AQG) and explaining why the “test-to-fail” standard principle is overtaking legacy “test-to-pass” rules; and third, summarizing the unique …