In high-risk fields such as medical, aerospace, and automotive, IPC classifications determine PCB reliability and safety. Class 3 represents the highest standard, requiring zero tolerance for defects, complete via filling, adequate copper annular rings, and rigorous inspections to ensure operation under extreme conditions, while Class 2 suits long-term use in non-critical equipment with minor cosmetic flaws allowed. Class 3’s strict criteria cover component placement, soldering, plating thickness, and environmental testing—adding cost and production time, but far outweighing the risks of failure in life- or safety-critical systems. Thus, defining high-risk equipment as Class 3 during design is essential, making IPC classification a core safeguard rather than an option.