Group your clients by how they've paid you in the past, then vary three things for each group: how you collect, when the first reminder goes out and how far escalation runs. Keep the wording of your reminders the same for everyone. You can build the groups from twelve months of paid invoices in an afternoon and refresh them every quarter.
In this article
The short version
- Group clients by how they've paid before, not by invoice size or sector.
- A minority of clients tends to account for about half of late payments.
- Vary how you collect, when the first reminder goes out and how far you escalate.
- Keep the wording of reminders the same for every group.
- Re-run the groups every quarter, because clients move both ways.
Why group clients by payment history
Late payment tends to be concentrated in a minority of clients. In Adfin's payment data, among repeat clients who had paid at least five invoices themselves, 27.4% were never late once, while the 24.3% who were late on most invoices accounted for 51.9% of all late payments. Your own ledger will differ, but it suggests a fairly small set of names is likely to be behind about half of your chasing.
Payment history tends to sort clients better than invoice size does. In the same data, large invoices weren't consistently paid later than small ones, so they need an approval check before the due date but not a group of their own.
Four groups and how to treat each one
Four groups is usually enough, plus a default for clients you don't know yet.
| Group | How to spot it | What you do differently |
|---|---|---|
| Pays every time | Never late across five or more invoices | Invoice and a due-date reminder, nothing more |
| Slips by a few days | Late sometimes, nearly always within a week | Scheduled reminders, no calls, no interest |
| Late most months | Late on about half their invoices or more | Change how you collect: direct debit, instalments or payment upfront |
| Late and quiet | Late and not replying, or a balance past 60 days | A named owner, statements, a pause on new work, then a formal notice |
| No history yet | Fewer than five invoices with you | Your default rules until there's a record |
Pick your thresholds and write them down. For example: nothing late for the first group, up to about 40% of invoices late for the second, more than that for the third, and anything unanswered for 30 days moves to the fourth.
How you collect tends to make the most difference. A client who's late most months is a strong candidate for direct debit or an instalment plan, so their payment stops depending on them remembering. You can also vary terms at the next fee review, when the first contact goes out (your reliable group may not need a reminder at all, while your late group gets a check before the due date), and who owns each group.
Keep the wording the same across every group. Different tones for different clients read as inconsistency the first time two of them compare notes, and the schedule and the collection method are likely to matter more than the words.
How to build the groups from your records
- Export twelve months of paid invoices with the client, the due date and the date the money arrived. Your accounting software can do this.
- Work out how many days late each invoice was, from the due date and the payment date. A simple overdue flag tells you whether it was late but not by how much.
- Treat direct debit separately. The money can reach your bank a few working days after the due date even when the client paid exactly on time, so judge those invoices by the collection date.
- For each client, count their invoices and the share that arrived after the due date. Anyone with fewer than five goes into your default group.
- Sort the rest, cut at your thresholds and read the names. Where a client lands somewhere surprising, check the record before trusting your impression, which may come from a single phone call.
- Write the rules on one page, against each group, not against individual clients' names.
How to keep the rules running
Re-run the sort every quarter. Clients move both ways: someone who has slipped three months running probably belongs in a different group, and someone who has paid six invoices on time since a bad spell can move back up.
The rules are easy to write and hard to apply by hand across a few hundred clients. In Adfin, you can run a separate agent for each group, each with its own reminder schedule, channels and collection method, and move a client from one agent to another when they change group. For a single client you can switch individual tasks such as statements or late fees on or off, or pause reminders while you talk. Adfin's collection agents can also learn each client's pattern, such as one who replies to a text but ignores email, and act on it within the limits you set.
Some of it still needs you: the client who rings to say they're in trouble, the disputed invoice and the decision to pause work for a long-standing name.
Common questions
How should you group customers for credit control? By how they've paid you before. Work out the share of each client's invoices that arrived after the due date, then group them as never late, sometimes late, late most months, and late and unresponsive.
Is it better to group clients by invoice size or payment history? Payment history. Large invoices need an approval check before the due date, but they aren't reliably paid later than small ones.
How many chasing rules do you need? Four groups plus a default for new clients covers most ledgers, and it's a number you can apply consistently.
Where do you put a client with no payment history? On your default rules, usually the same as the second group, until they've paid at least five invoices.
Should you write different reminder emails for different clients? The schedule and the collection method are worth varying far more than the wording. Different tones for different clients can look inconsistent.
How often should you review your client groups? Quarterly. Less often and a client who has started slipping can run up several more late invoices before you notice.
Sources
- Adfin Help Centre - How to get paid with customer agents (accurate as of October 2026) https://support.adfin.com/en/articles/15288807-how-to-get-paid-with-customer-agents
- Adfin Help Centre - How to pause reminders and collection in Adfin (accurate as of October 2026) https://support.adfin.com/en/articles/13870679-how-to-pause-reminders-and-collection-in-adfin
- Adfin - Credit control (accurate as of October 2026) https://www.adfin.com/credit-control
- GOV.UK - Late commercial payments: charging interest and debt recovery (accurate as of October 2026) https://www.gov.uk/late-commercial-payments-interest-debt-recovery
