change in accounting estimate

Accounting estimates include the estimated salvage value and the estimated useful life of depreciable assets, estimated percentage of bad debts expense, estimated percentage of units to be repaired or replaced during a warranty period, and routine estimates of monthly expenses for utilities and other expenses. When a change is needed to one of these estimates, the change can affect the current and future periods only. Previous periods are not restated for changes in estimates. (Corrections of errors require a restatement of a prior period amount.)