Explain amortisation period in relation to intangible assets. When this period needs to be reviewed and changed?

Amortisation on Intangible Assets The depreciable amount of an intangible asset should be allocated on a systematic basis over the best estimate of its useful life. There is a rebuttable presumption that the useful life of an intangible asset will not exceed ten years from the date when the asset is available for use. Amortisation should commence when the asset is available for use. As the future economic benefits embodied in an intangible asset are consumed over time, the carrying amount of the asset is reduced to reflect that consumption. This is achieved by systematic allocation of the cost of the asset, less any residual value, as an expense over the asset's useful life. Amortisation is recognised whether or not there has been an increase in, for example, the asset's fair value or recoverable amount. Given the history of rapid changes in technology, computer software and many other intangible assets are susceptible to technological obsolescence. Therefore, it is likely that their useful life will be short. If control over the future economic benefits from an intangible asset is achieved through legal rights that have been granted for a finite period, the useful life of the intangible asset should not exceed the period of the legal rights unless the legal rights are renewable; and renewal is virtually certain. The amortisation period should be reviewed at least at each financial year end. If the expected useful life of the asset is significantly different from previous estimates, the amortisation period should be changed accordingly.