When the management has determined a useful life to an asset, the depreciable amount (acquisition cost or carrying value less any residual value if applicable) is allocated on a systematic basis over its useful life. In other words the value is expensed over determined months using one of the two methods available.
First things first, the amortization starts when the asset is available for use and ceases when the asset is derecognized or reclassified as held for sale. The period between those two dates is the expected period of useful live. Continue reading