Xerography is based on the development of latent electrostatic images by triboelectrically-charged toner particles. In a two-component (TCD) developer, the toner particles are triboelectrically charged via energetic mixing with polymer-coated magnetic carrier beads. Since the TCD xerographic development process is non-linearly related to TCD developer properties (e.g. toner charge, toner supply, powder flow mechanics, etc.), TCD aging can be a major factor for eventual imaging failure. In this review, simple parametric models of triboelectric charging and xerographic development will be combined to illustrate some of the major effects of changes in carrier bead surface chemistry on insulative TCD xerographic development.