Simulations are reported for the cyclic voltammetry of both electrochemically reversible and irreversible one electron processes at porous electrodes where the potential cycle is applied for multiple cycles. It is shown that an 'ultimate state' is approached asymptotically and that the long time voltammogram can be very different in terms of the peak height from those recorded in the first scan though peak-to-peak potential separations are conserved. The implications for the experimental study of porous electrodes are considered.