This paper presents a few selected cases of recent experimental work on the measurement of transport and reaction properties of electron and ion swarms in gases and their usefulness to either validate or derive sets of collision cross sections which are essential for the understanding, simulation and modelling of many types of gas discharges. The paper discusses several key examples of measured electron/ion drift velocities (mobilities), longitudinal diffusion coefficients, effective ionization coefficients, and ion-molecule reaction rates with gases through which new sets of cross sections have been obtained. All the systems discussed contemplate the measurement of the pure gas and its mixture with N2 or rare gases for which reliable cross section sets are well known, thereby serving as a test to the newly derived cross sections for the pure gas.