As WPT technologies developed, especially for use in biomedical and implantable devices, system-level energy management became a critical aspect of ensuring secure, efficient, and reliable operation. This chapter introduces advanced techniques that extend beyond basic power conversion, focusing on how energy is intelligently managed, reused, and adapted in real-world applications. First, this chapter presents a secure energy backup receiver designed for cryptographic wireless authentication tags. These tags play a vital role in protecting against counterfeiting in supply chains. A novel energy backup unit (EBU), equipped with non-volatile flip-flops and a clock-controlled voltage doubler, ensures secure data retention even during intentional power disruptions like power-glitch attacks. Next, the optimal reuse energy receiver addresses inefficiencies in conventional wireless back telemetry used in medical implants. Instead of dissipating energy during data transmission, the proposed system temporarily stores the telemetry energy and reuses it for device operation. An adaptive dual-input low-dropout (LDO) regulator intelligently selects between direct and stored energy sources, improving energy efficiency during telemetry and enabling simultaneous power reception and data transmission. Lastly, application-specific WPT solutions are explored through an adaptive power system for deep brain stimulation (DBS). Traditional fixed-voltage designs are replaced with a closed-loop adaptive rectifier, which adjusts its output in real time based on the requirements of stimulation sites. A voltage readout channel enables precise feedback, ensuring that only the necessary power is delivered, thereby improving safety and energy efficiency. Together, these system-level strategies mark a significant step forward in the practical deployment of wireless power for secure, efficient, and intelligent device operation.