Crystal oscillators are pivotal in electronic circuits, providing a stable frequency output across diverse operational conditions. This investigation aims at estimating the fatigue lifetime under random vibration of a crystal oscillator mounted on a printed circuit board (PCB) under various boundary conditions such as fixed-fixed and cantilever. The accuracy and reliability of finite element models were ensured by validating them against experimental data by comparing transmissibility results. After validation, further simulations were developed to investigate how various locations affected the crystal oscillator’s fatigue lifetime and demonstrate how positional changes affect fatigue lifetime under random vibrations. Steinberg’s three-band method was employed to estimate the fatigue lifetime of the crystal oscillators. The results identify crucial locations in low-stress areas, extending the crystal oscillator’s operating life. The current study provides design engineers with practical suggestions for optimising the positioning of electrical components on printed circuit boards. Strategically placing crystal oscillators can substantially enhance their lifespan and optimise performance, bolstering electronic devices’ overall reliability and durability.