One way to define that is in terms of the customer: quality (no defects), calendar time to deliver, benefit to customer, and value (cost-benefit ratio). So you

One way to define that is in terms of the customer: quality (no defects), calendar time to deliver, benefit to customer, and value (cost-benefit ratio). So you can say things like, "if we refactor this code now, we can schedule less time on maintaining it in the future, spend less unscheduled time fixing bugs in the future, and deliver features in less time with less effort."