The crystal field is one of the major interactions in rare-earth compounds. Neutron spectroscopy has become the key tool to measure the crystal-field transitions in metallic systems. This has been demonstrated for almost 1000 metallic rare-earth compounds in the past 30 years which resulted in a detailed understanding of the various physical effects caused by the crystal-field splitting. One may conclude that the determination and description of crystal fields in metallic rare-earth systems is now well established and has become a standard technique. Yet the past years have seen exciting developments in different applications where the crystal-field concept attained increasing and sometimes even crucial importance. This is exemplified for two applications: Firstly, the novel principle for cooling by adiabatic pressure application which is based on the occurrence of a pressure-induced structural and/or magnetic phase transition where the point symmetry at the rare-earth site is changed involving a change in the degeneracy of the crystal-field states. Secondly, the observation of anomalies in the linewidth of crystal-field transitions in high-temperature superconductors which reveals direct information on the doping and isotope dependence of the pseudogap.