A prerequisite for the development or optimization of heterogenous catalysts is a comprehensive understanding of the reaction mechanism and kinetics at the level as elementary as possible. In comparison with steady-state catalytic tests typically used for this purpose, non-steady-state (transient) studies provide deeper insights due to higher time resolution. For several decades, temporal analysis of products (TAP) and steady-state isotopic transient kinetic analysis (SSITKA) have been successfully applied to the analysis of various heterogenous reactions. In this review, we highlight the contributions made by TAP and SSITKA studies between 2017 and 2023 to the understanding of reaction mechanisms and to the derivation of microkinetics. The versatility of these methods is illustrated by the examples of oxidative coupling of methane, CO/CO2 hydrogenation to hydrocarbons or methanol, metathesis of ethylene with 2-butenes to propene, acrolein oxidation to acrylic acid, methanol conversion to olefins and non-oxidative propane dehydrogenation to propene. We also provide our personal views on possible developments in this area.