The discussion of multistep reactions here is linked to their experimental study, as the two are intimately connected. Four experimental methods with distinct requirements can be identified. If the rate constant of the rds/src-step is large and only low overpotentials can be probed before the current becomes dominated by mass transport, the micropolarization method is most appropriate. In contrast, when the rate constant of the src step is small, the Tafel method can be used. (3) In any case, a full B-V model can be fitted to the i-V curve, however this requires knowledge of the reaction mechanism and a corresponding microkinetic model that applies over a wide potential range. (4) Lastly, impedance spectroscopy can in principle be used at any potential and does not require full knowledge of the system. All methods have in common that they yield an exchange current density for the overall reaction, but despite its ubiquity, the exchange current density cannot be universally defined for multistep reactions. While for a single step reaction or an elementary step it captures the magnitude of the forward and backward current at the equilibrium potential, such a definition is meaningless for multistep reactions with different rate constants and formal potentials. To make matters worse, different experimental methods lead to different exchange current densities. Among them, the micropolarization method provides the most appropriate definition as it corresponds to the equilibrium potential. In contrast, exchange current densities obtained through the Tafel analysis are delicate, in the sense that they may be strongly dependent on the chosen potential range, which will be shown presently, starting from the discussion of the micropolarization and the Tafel method in the absence of mass transport limitations.