The loss in usefulness of an asset, occasioned by the approach to the state of economic uselessness through progress of the arts; economic inutility arising from external causes; disappearing usefulness resulting from invention, change of style, legislation, or other causes having no physical relation to the object affected. It is distinguished from exhaustion, wear and tear, and deterioration, in that these terms refer to a functional loss arising out of a change in physical condition.
N.Y. Comp. Codes R. & Regs. Tit. 10 § 451.197