5G mobile operators aim to deliver a superior user experience to their smartphone subscribers. This experience is not only about features like bandwidth, coverage and reliability, but also how long they can use their devices over the course of the day. Longer battery life can be achieved by reducing the energy consumption of the 5G mobile device, which is equally critical to sustainability goals. 3GPP has introduced a comprehensive toolbox of device energy saving features in the 5G New Radio (NR) Releases 15–17 that can increase battery life, thus providing a superior user experience. The toolbox is the focus of this paper, with an emphasis on the recent enhancements defined in NR Release 17.