Final answer:
Expenditures are debited when supplies are acquired or purchased under the purchases method. This follows the accrual basis of accounting, where expenses are recorded at the time of occurrence. The supplies expense or inventory account is debited and cash or accounts payable is credited.
Step-by-step explanation:
Under the purchases method, expenditures are debited when supplies are acquired or purchased. In accounting, this approach is consistent with the accrual basis of accounting where expenses are matched with the related purchases at the time the expense occurs, rather than when payment is made. When supplies are bought, the accounting entry would involve debiting the supplies expense or inventory account to increase it, and crediting the cash or accounts payable to reflect the payment or payment obligation for these supplies.