An image forming apparatus includes a carrier on which an electrostatic
latent image is formed, a plurality of development cartridges which
develop the electrostatic latent image with toner to form a toner image
to be transferred to a recording sheet, and a changeover unit which
changes the development cartridges so that any one of the development
cartridges is moved so as to face a surface of the carrier for
development. At least two of the development cartridges contain the same
color toners. The changeover unit repeatedly changes the development
cartridges before an expiration of lifetime of one of the development
cartridges which is positioned so as to face the carrier for the
development.