Obsolescence

Obsolescence means:
a loss in the value of property due to changes in technology or popularity which are unrelated to the physical condition of the property itself. An asset becomes obsolete when it has no fair market value or is no longer used. Inventory, for example, may be written off by the taxpayer when it becomes obsolete. For some materials, such as published books, however, inventory must be destroyed to qualify for a write-off. Contrast depreciation; wear and tear.

See Depreciation in the United States Encyclopedia of Law and Depreciation in the World Encyclopedia of Law.