[en] In this paper, we discuss several categories of decay data which have contributed to low-energy nuclear physics, indicate some of the ways they are useful in solving problems in other areas, and identify needs for further measurements. Illustrations include half-life and emission-probability data of actinide nuclides important for reactor technology and useful as reference standards for nuclear-data measurements. Decay data of highly neutron-rich fission-product nuclides are important in such diverse areas as astrophysics and reactor-safety research. Some of these data needs and experimental approaches suitable for satisfying them are presented. 17 refs., 1 tab