Abstract
This paper points out that degradation is not a phenomenon to be prevented, but should be considered from the standpoint of customization and breaking in. Human Machine Interface has been discussed mostly from the standpoint of one time value, i.e., based on the final functions at the time of delivery. But in the days of diversification and personalization, Human Machine Interface should consider such degradation as customization or personalization to increase lifetime value of a product or a machine.
