The loss in value of an asset (or broadly an item) as a result of to a decrease in demand for that of asset or item over time (after its acquisition). Such items include machinery and equipment that get obsolescent due to changes in techniques, tastes, methods of production, or circumstances that could not be reliably predicted at the time of acquisition.

For example, equipment may become abnormally obsolete because the goods it produces lose their appeal to consumers due to changes in tastes or appearance of alternatives, with better functionality or cheaper prices, etc. Cheaper goods may become available, over time, thanks to new techniques that allow production with improved inputs in terms of less labor or materials, and so on. Furthermore, abnormal obsolescence may occur for enhanced regulatory requirements such as improved health and safety measures introduced to the production process.