results from or measures the using up of an asset (e.g., depreciation) or incurrence of a liability (e.g., warranty expense) to obtain revenue in the current period. An expense can apply to the cost of merchandise sold or services rendered. Expenses apply to the ordinary course of business (e.g., salary expense) rather than to incidental transactions (e.g., fire loss). Expenses are deducted from revenue to derive net income. An expense account is maintained for each type of expense for control purposes.