When doing cash purchases, what side do the entries go on the customer's account?

In accounting, when a customer makes a cash purchase, it increases the expense or the asset associated with that purchase. This transaction reflects a decrease in the customer's cash balance and an increase in the value of what they purchased.

When you record a cash purchase in the customer’s account, you generally debit the accounts related to the expense or asset because debiting indicates an increase in these types of accounts. For example, if a customer buys inventory or supplies, those account balances go up due to the purchase, which is recorded on the debit side. At the same time, the cash account is credited, reflecting the outflow of cash from the customer's account. This dual effect is fundamental to the double-entry accounting system.

Therefore, since the transaction results in an increase in the customer's expense or asset, it logically belongs on the debit side of the customer's account.