A method, and device incorporating the method, permits adjustment of the on time of a light source that illuminates a display within a handheld wireless communications device. The on time may be adjusted by the amount of information to be displayed, the font size of the information, the behavioral characteristics of the end user, the type of viewing activity, and the like. An optional dim mode permits the end user to be made aware that the light illuminating the display is about to be shut off.