1. A method for testing inkjets for defects in an inkjet device, comprising: determining, based on the likelihood that a given inkjet is defective, whether to perform an inkjet defect test; identifying which inkjets to test based on (1) the likelihood that a given inkjet is defective and (2) a predicted failure rate for each of the inkjets, the number of identified inkjets being less than the total number of inkjets in the inkjet device; marking a test image on an intermediate substrate using only the identified inkjets, if it is determined to perform an inkjet defect test; evaluating the test image for defects by using an image sensor; tracking characteristics of each inkjet related to failure of that inkjet; and quantifying the tracked characteristics, wherein the step of identifying which inkjets to test based on a predicted failure rate for each of the inkjets in the inkjet device comprises: comparing the quantified characteristics of each inkjet in the inkjet device with a predefined limit; identifying an inkjet for defect testing if that inkjet's quantified characteristics is over the predefined limit; and adjusting the quantified characteristics for each inkjet in the inkjet device, if that inkjet has a history of failure, based on a position of that inkjet within a predetermined distance relative to an edge of the sheet media.