1. STATEMENT OF SIGNIFICANT ACCOUNTING POLICIES CONTINUED  (p) Amortisation  (q) Impairment  Calculation of recoverable amount  Reversals of impairment  (r) Trade and Other Payables  Page 37 of 80  Liabilities are recognised for amounts to be paid in the future for goods and services received, whether or not billed to the  consolidated entity. Trade accounts payable are normally settled within 60 days. Trade and other payables are stated at  cost.  An impairment loss is reversed only to the extent that the asset’s carrying amount does not exceed the carrying amount  that would have been determined, net of depreciation or amortisation, if no impairment loss had been recognised.  In respect of other assets, an impairment loss is reversed if there has been a change in the estimates used to determine  the recoverable amount.  An impairment loss in respect of goodwill is not reversed.  An impairment loss in respect of receivables carried at amortised cost is reversed if the subsequent increase in  recoverable amount can be related objectively to an event occurring after the impairment loss was recognised.  Subject to an operating segment ceiling test, for the purposes of goodwill impairment testing, CGUs to which goodwill  has been allocated are aggregated so that the level at which impairment is tested reflects the lowest level at which  goodwill is monitored for internal reporting purposes. Goodwill acquired in a business combination is allocated to groups  of CGUs that are expected to benefit from the synergies of the combination.  The recoverable amount of other assets is the greater of their fair value less costs to sell and value in use. In assessing  value in use, the estimated future cash flows are discounted to their present value using a pre-tax discount rate that  reflects current market assessments of the time value of money and the risks specific to the asset. For an asset that  does not generate largely independent cash inflows, the recoverable amount is determined for the cash-generating unit  to which the asset belongs.  The recoverable amount of the consolidated entity’s receivables carried at amortised cost is calculated as the present  value of estimated future cash flows, discounted at the original effective interest rate (i.e. the effective interest rate  computed at initial recognition of these financial assets). Receivables with a short duration are not discounted.  Impairment losses recognised in respect of cash-generating units are allocated first to reduce the carrying amount of any  goodwill allocated to the cash-generating unit (group of units) and then, to reduce the carrying amount of the other assets  in the unit (group of units) on a pro rata basis.  An impairment loss is recognised whenever the carrying amount of an asset or its cash generating unit exceeds its  recoverable amount. Impairment losses are recognised in the profit and loss unless the asset has previously been  revalued, in which case the impairment loss is recognised as a reversal to the extent of that previous revaluation with any  excess recognised through the profit and loss. The carrying amount of the consolidated entity’s assets, other than inventories (see paragraph (m)), and deferred tax  assets (see paragraph (i)), are reviewed at each statutory reporting date to determine whether there is any indication of  impairment. If any such indication exists, an impairment test is performed. The consolidated entity performs impairment  testing of goodwill and intangibles with indefinite useful lives annually.  Amortisation methods, useful lives and residual values are reviewed at each reporting date. Amortisation is charged to the profit and loss on a straight-line basis over the estimated useful lives of intangible assets  unless such lives are indefinite. Goodwill and intangible assets with an indefinite life are not amortised but are  systematically tested for impairment at each annual balance sheet date. Works contracts which are assigned a value  are amortised over the life of the contract from the date they are available for use.  Amortisation is calculated over the cost of the asset, or other amount substituted for cost, less its residual value.  Cardno Limited and its Controlled Entities for the year ended 30 June 2010 Notes to the Consolidated Financial Statements 