Marcy LaRont speaks with Laura Martin, Director of Strategic Markets at Isola, about PCB reliability in harsh environments across aerospace, automotive, and defense applications. Martin explains that reliability under pressure involves managing cyclic strain within composite materials—not just meeting temperature limits. Thermal cycling, Z-axis expansion, moisture under bias, and anisotropic behavior all contribute to long-term fatigue and failure. Common failure mechanisms such as plated through-hole cracking and interfacial delamination are discussed, highlighting the increasing importance of material selection based on strain management rather than just Tg. The conversation emphasizes designing for real-world stress factors to ensure long-term durability and performance.