Final answer:
Bad debt expense is estimated by companies to match the expense of potential bad debts with the revenue generated in the same period.
Step-by-step explanation:
In estimating bad debt expense for a period, companies generally accrue either an amount based on a percentage of total sales or an amount based on a percentage of accounts receivable after adjusting for any balance in the allowance for doubtful accounts.
For example, a company may estimate bad debt expense as 2% of total sales or 5% of accounts receivable. This allows the company to match the expense of potential bad debts with the revenue generated in the same period, adhering to the matching principle.