Main  Principles  of Depreciation Accounting :

The depreciable amount of a depreciable asset should be allocated on a systematic basis to each accounting period during the useful life of the asset.

21. The depreciation method selected should be applied consistently from period to period. A change from one method of providing depreciation to another should be made only if the adoption of the new method is required by statute or for compliance with an accounting standard or if it is considered that the change would result in a more appropriate preparation or presentation of the financial statements of the enterprise. When such a change in the method of depreciation is made, depreciation should be recalculated in accordance with the new method from the date of the asset coming into use. The deficiency or surplus arising from retrospective recomputation of depreciation in accordance with the new method should be adjusted in the accounts in the year in which the method of depreciation is changed. In case the change in the method results in deficiency in depreciation in respect of past years, the deficiency should be charged in the statement of profit and loss. In case the change in the method results in surplus, the surplus should be credited to the statement of profit and loss. Such a change should be treated as a change in accounting policy and its effect should be quantified and disclosed.

22. The useful life of a depreciable asset should be estimated after considering the following factors:

(i) expected physical wear and tear;

(ii) obsolescence;

(iii) legal or other limits on the use of the asset.

23. The useful lives of major depreciable assets or classes of depreciable assets may be reviewed periodically. Where there is a revision of the estimated useful life of an asset, the unamortised depreciable amount should be charged over the revised remaining useful life.

24. Any addition or extension which becomes an integral part of the existing asset should be depreciated over the remaining useful life of that asset. The depreciation on such addition or extension may also be provided at the rate applied to the existing asset. Where an addition or extension retains a separate identity and is capable of being used after the existing asset is disposed of, depreciation should be provided independently on the basis of an estimate of its own useful life.

25. Where the historical cost of a depreciable asset has undergone a change due to increase or decrease in long term liability on account of exchange fluctuations, price adjustments, changes in duties or similar factors, the depreciation on the revised unamortised depreciable amount should be provided prospectively over the residual useful life of the asset.

26. Where the depreciable assets are revalued, the provision for depreciation should be based on the revalued amount and on the estimate of the remaining useful lives of such assets. In case the revaluation has a material effect on the amount of depreciation, the same should be disclosed separately in the year in which revaluation is carried out.

27. If any depreciable asset is disposed of, discarded, demolished or destroyed, the net surplus or deficiency, if material, should be disclosed separately.

28. The following information should be disclosed in the financial statements:

(i) the historical cost or other amount substituted for historical cost of each class of depreciable assets;

(ii) total depreciation for the period for each class of assets; and

(iii) the related accumulated depreciation.

29. The following information should also be disclosed in the financial statements alongwith the disclosure of other accounting policies:

(i) depreciation methods used; and

(ii) depreciation rates or the useful lives of the assets, if they are different from the principal rates specified in the statute governing the enterprise.