employed
2574 Points
Joined May 2008
I think what you are asking, is about the issue of capital maintenance. The purpose of depreciation is manifold:
1. Matching principle - amortising the cost of an asset over the accounting periods during which its benefits will be derived.
2. Replacement of assets - to set apart a portion of profit for replacement of assets at the end of their lives, so as to ensure the capacity isnt drastically reduced at the end of its life, and consequently affect going concern.
3. In taxation - an allowance to encourage investment, compensating a business for the time value of money (so no indexation on depreciable asset)
Capital maintenance - in point 2 above. When depreciation is provided each year, it reduces the profit distributable to owners. There is no cash outflow as a result of this charge to profit. So theoretically, at the end of an asset's useful life, enterprise has set apart from profits, an amount covering "depreciable value", it can sell the asset for "residual value" and, theoretically, have a cash balance to buy a new asset. Thus, the asset side of balancesheet is kept "intact".
The sad part of this theory: even if all profits are realised in cash, depreciation is on historical cost of an asset and ignores its replacement cost. So it doesn't really help you replace assets. Fair value accounting is required to solve this problem.