Any significant change in the conditions of use of the asset justifies the revision of the plan during its execution. Whether or not their useful life is limited, fixed asset items are subject to depreciation when their inventory value is less than their book value and if the loss of value is expected to be permanent. Depreciation and amortisation are recorded separately on the assets side as a reduction in the value of the corresponding items. Provisions are established for risks and charges, clearly specified as to their purpose, which events that have occurred or are in progress make probable. Impairments and provisions are charged to profit or loss when the reasons for which they were recorded have ceased to exist. As an exception, impairment losses relating to goodwill are never charged to income.