historical cost is always a relevant measure of an asset
Historical cost In accounting under the traditional historical cost paradigm, historical cost is the original nominal monetary value of an economic item.[1] Historical cost is based on the stable measuring unit assumption. In some circumstances, assets and liabilities may be shown at their historical cost, as if there had been no change in value since the date of acquisition. The balance sheet value of the item may therefore differ from the real value.
Financial cost of the Iraq War Official calculations stated that the Iraq and Afghanistan wars combined cost Â£20.3 billion (up to but not beyond June 2010).[23]