method of depreciation used should reflect the pattern in which the future economic benefits of the asset are expected to be consumed by the entity. i.e. in the ratio in which benefits are consumed. the depreciation method selected to an asset should be reviewed at least at each financial year end. if there has been a significant change in the expected pattern of consumption of the future economic benefits emboided in the asset, the method should be changed to reflect the changed pattern. such a change in method of depreciation should be accounted for as a change in an accounting estimate in accordance with AS 5.