This paper by Splett and Handel, presented at the International Symposium on Single Photon based Quantum Technologies in Berlin, examines quantum theory of 1/f frequency fluctuations Part 2, focusing on quantum 1/f optimization of quartz resonators, electronics, MEMS, clocks, piezotransducers, and resonant sensors. The comprehensive work provides practical design strategies for minimizing quantum 1/f frequency noise across diverse applications, offering specific optimization approaches for different device types to achieve ultimate frequency stability in precision timing and sensing systems.