Invoice math

Rules for turning an invoice's age and balance into the right action.

Aging buckets

Measure age from the invoice due date (not issue date).

Reminder tiers

• Courtesy notice — friendly heads-up that payment is due soon. No pressure.
• First reminder — a polite nudge with the amount, due date, and pay link.
• Second reminder — firmer; restate the balance and how many days overdue.
• Final notice — clear consequence framing; still professional.
• Hold for human — do not send. Surface in the summary for a person.

Dunning cadence

• Send at most one reminder per invoice per run, and never two reminders to the same invoice within 72 hours — check the last-sent log first.
• Escalate a tier only when the invoice crosses into the next bucket, not on every run.
• Once an invoice is paid, stop immediately and note it in the summary.

Stop-for-human triggers

Regardless of bucket, do not send and hand off to a person when the invoice is:

• over the approval threshold for the account,
• flagged disputed, or
• marked for collections / legal.