1. A method of operating a battery-operated device, comprising: for each task of one or more tasks for each application of a plurality of applications of the battery-operated device: receiving, from a user of the battery-operated device, user input defining a usage parameter for the application for the task that corresponds to a desired amount of usage of the application for the task; determining an estimated amount of battery life of a battery of the battery-operated device that is sufficient to provide the desired amount of usage of the application for the task; determining whether the estimated amount of battery life is available; and if the estimated amount of battery life is available, allocating an amount of battery life of the battery to the application for the task corresponding to the estimated amount of battery life; and wherein the one or more tasks for each of the plurality of applications form a plurality of tasks, and the method further comprises enabling the user to prioritize the plurality of tasks.