The appliance for treating the hair, having two arms to be closed over the hair to be treated, at least one of the arms carrying a refill of hair treatment product, the appliance having an electronic control circuit with an electronic memory, this circuit being designed to detect the closure of the arms and the fitting of the refill, the appliance having a steam generator for outputting steam onto the hair and at least one heated straightening plate, the appliance being designed to increment a variable in the memory during the use of the appliance after the refill has been changed and to pass into a downgraded mode of operation in which the operation of the steam generator and/or of the straightening plate is modified when the variable exceeds a first predefined threshold.