The required frequency and disruptive method in which existing subjective measures of mental workload are collected make them infeasible for many types of task allocation decisions. In this paper, we present a method for continually estimating workload without interrupting the operator. When expressed as a time-series, this continual workload assessment becomes a workload profile which can serve purposes before, during, and after task execution. We identify five thrusts areas for using workload profiles which cannot be accomplished using existing workload measures. These thrust areas include characterization of workload over time; identifying the impacts of task management strategy on mission accomplishment; evaluating potential effects of systems design options—including automation—on task performance; informing manpower allocation decisions; and enhancing physiological computing and neuroergonomic research.