Accounting estimate changes must be recognised prospectively and disclosed when they affect current or future periods. Revisions to accounting estimates are recognised prospectively: include the effect in profit or loss for the period of change if it affects only that period, or in that period and future periods if it affects both. Where a change affects assets, liabilities or equity, adjust the carrying amount of the related item in the period of change. Disclose the nature and amount of any change that affects the current period or is expected to affect future periods; if estimating the future effect is impracticable, disclose that fact.