1. A method of operating non-volatile storage, the method comprising: determining information indicative of a first impedance characteristic of a first reversible resistance-switching element and a second impedance characteristic of a second reversible resistance-switching element, the first and the second resistance-switching elements are to be programmed from a low resistance data state to a higher resistance data state; determining a first programming signal for the first reversible resistance-switching element based at least in part on the first impedance characteristic and a second programming signal for the second reversible resistance-switching element based at least in part on the second impedance characteristic, the first and second programming signal to apply to the first and the second reversible resistance-switching elements; applying the first programming signal to the first reversible resistance-switching element as an initial programming signal to move the resistance of the first reversible resistance-switching element from the low resistance data state at least partially to the higher resistance data state, the first programming signal is applied at a time when the first reversible resistance-switching element has the first impedance characteristic; and applying the second programming signal to the second reversible resistance-switching element as an initial programming signal to move the resistance of the second reversible resistance-switching element from the low resistance data state at least partially to the higher resistance data state, the second programming signal is applied at a time when the second reversible resistance-switching element has the second impedance characteristic.