A wasting asset declines in value over multiple time periods. This decline is reflected in the accounting records by recording depreciation expense for these assets. The depreciation period is intended to match the same time period over which the decline in valuation occurs. Examples of wasting assets are computer equipment, vehicles, and furniture.
The same concept applies to natural resources, such as minerals, which decline in value as they are consumed over time. Depletion is used to reflect this change in the accounting records.
The concept also applies to options of all types; their value drops to zero as of the expiration date of these instruments.
Some fixed assets may increase in value over time, but are still depreciated. For example, the market value of a building may increase in accordance with changes in local market conditions.