Derating is the process of operating machinery or electronic components at a reduced capacity, speed, or power output than their rated maximum to improve reliability, extend their lifespan, and prevent failures caused by stress factors like high ambient temperatures, increased altitude, or non-ideal voltage conditions. By deliberately lowering the stress on the equipment, derating creates a larger safety margin between the component's design limits and the applied stresses, thereby reducing degradation and enhancing performance under challenging conditions.