1. A non-transitory computer readable storage medium storing therein a storage device usage management program to be executed by a computer, the storage device usage management program being a program for managing usage of a limited-life non-volatile storage device that is included in an electronic device and on which a limit on the number of times of writing therein is imposed, wherein the storage device usage management program comprises: a first program code that causes the computer to classify, as one of a plurality of classes, a job for which execution is requested by a user, wherein a request for job execution includes to-be-used function information; a second program code that causes the computer to acquire an amount of data to be written into the non-volatile storage device by execution of the job for which execution is requested from the to-be-used function information; a third program code that causes the computer to calculate an efficiency index for each of the plurality of classes based on an execution evaluation value of each of the plurality of classes and the amount of data to be written by execution of the at least one job that has been already classified as belonging to a class of the plurality of classes; a fourth program code that causes the computer to determine from among the plurality of classes, a class having an efficiency index of no greater than an efficiency threshold value as an execution suspending class, or a specific number of classes in ascending order of the efficiency index, a class having a lowest efficiency index as the execution suspending class; a fifth program code that causes the computer to determine whether or not the job for which execution is requested belongs to the execution suspending class; a sixth program code that upon determining that the job belongs to the execution suspending class: allows execution of the job for which execution is requested, if determined that the job is to be executed based on user privilege; otherwise suspend execution of the job for which execution is requested, and a seventh program code that causes the computer to allow execution of the job for which execution is requested when the job does not belong to the execution suspending class; and an eighth program code that causes the computer to update the execution evaluation value of a class to which the executed job belongs and at least one of a sum and an average value of the amount of data written by execution of the at least one job.