Customer credit gets argued about
A notebook records but does not add up. At month end you walk the pages, and when a customer says they already paid there is no way to show them when or how much.
An up-to-date balance per customer
Every credit sale is recorded with a date and an amount, and the balance updates itself. The statement goes out over WhatsApp instead of being explained at the counter.
- A balance per customer, with nothing added up by hand
- Every payment dated, so it is not disputed
- A per-customer ceiling, if you want one