Once a client has signed a SEPA direct debit mandate, an agency collects each month's retainer by sending the invoice, with the amount and collection date on it, at least 14 calendar days before the collection, unless the contract sets a shorter notice period. The fixed retainer can be collected in advance, and extra hours or rebilled costs can be added to a later invoice in arrears. Through Adfin, a retainer of up to €2,000 costs no more than €2.20 to collect by direct debit or bank transfer, while card payments aren't capped.
In this article
The short version
- Fix the collection date first, then work back to the invoice date.
- Invoicing on the 18th for the 5th gives 15 days' notice every month.
- Add extra hours in arrears to the next retainer invoice.
- A retainer of €200 to €2,000 costs €26.40 a year to collect through Adfin.
- Clients can ask their bank for a refund within eight weeks.
A collection date that works every month
A retainer suits direct debit because the amount and the date repeat. The client signs a mandate once, and after that nobody on their side has to approve a transfer each month.
The SEPA Direct Debit Core rules set the timing. Each collection needs a pre-notification at least 14 calendar days before it, unless you and the client agree a different period, and the invoice can be that notice. So fix the collection date first and work back to the invoice date.
February is the month that catches people out. If you collect on the 5th and invoice on the 20th, most months give you 15 or 16 days, but 20 February to 5 March is only 13 days in a normal year. Invoicing on the 18th instead gives you at least 15 days in every month. If you'd rather keep a later invoice date, agree a shorter notice period in your contract when the client signs the mandate.
Retainers with extra hours or rebilled costs
If your retainer covers a set scope, with extra hours or costs paid on the client's behalf, such as software or printing, billed on top, you won't know those amounts in advance. They can go on a later invoice in arrears, alongside the next month's fixed fee.
Take a client on a €1,400 monthly retainer who used five extra hours in October at €90 an hour. The invoice you send on 18 November carries December's retainer of €1,400 and October's extra hours of €450, and you collect €1,850 on 5 December. That single collection costs €2.20. Collecting the €450 separately would cost another €2.20, since 1% of €450 is €4.50 and the cap holds it at €2, plus 20c, so keeping both on one invoice saves a collection each month there are extras.
Show the hours, dates and rate on the invoice. The client can then check the extra lines before the collection date, which is a better time to raise a query than after the money has left their account.
What a year of retainer collections costs
Adfin charges 20c + 1% per successful payment, with no monthly fee, setup fee or contract. On direct debit and bank transfer the 1% part is capped at €2, which it reaches at €200, while cards have no cap. Over a year, the difference grows with the size of the retainer.
| Monthly retainer | By SEPA direct debit, per year | By standard card, per year |
|---|---|---|
| €150 | €20.40 | €20.40 |
| €750 | €26.40 | €92.40 |
| €1,400 | €26.40 | €170.40 |
| €1,850 | €26.40 | €224.40 |
Below €200 the method makes no difference to the fee. From €200 to €2,000, direct debit costs the same €26.40 a year whatever the retainer, so the larger the monthly fee, the more the payment method changes what you pay.
Queries, quiet spells and clients who already pay by direct debit
A client can ask their bank to refund any direct debit within eight weeks, no reason needed, or within 13 months if they say they didn't authorise it. A clear invoice and a named contact give a client with a query about a month's work someone to raise it with first. Adfin's free Essential credit control includes an aged debtors view where every client has an owner and next steps, plus unlimited reminders by email, SMS and WhatsApp for any invoice that isn't on direct debit or comes back unpaid.
If a client pauses their retainer for a while, the mandate stays usable, but under the SEPA rules a mandate that goes 36 months without a collection lapses, and the client would need to sign a new one.
If your retainer clients already pay by SEPA direct debit through another provider, they don't need to sign again when you move to Adfin. Their existing mandates come across with the next collection, and they're told before it's taken.
Common questions
Can I collect a retainer in advance by direct debit? You can, as long as the invoice or other notice reaches the client at least 14 calendar days before the collection, unless your contract agrees a shorter period.
How do I add extra hours to a retainer collection? Bill them in arrears on the next invoice, alongside the following month's retainer, and collect the total on the usual date. The notice on that invoice covers the full amount.
What does it cost to collect a €1,400 retainer by direct debit? Through Adfin, €2.20 a month, or €26.40 a year, because the 1% part is capped at €2 on direct debit and bank transfer. By standard card it would be €14.20 a month.
Why does February cause problems with direct debit notice? It's short, so an invoice date that gives 14 days in other months can give 13 in February. Invoicing on the 18th for a collection on the 5th leaves at least 15 days all year.
Can a client get a retainer collection refunded? Their bank will refund an authorised collection if they ask within eight weeks, and an unauthorised one within 13 months.
Does a direct debit mandate expire if a retainer is paused? It lapses if no collection is made under it for 36 months. A shorter pause leaves it in place.
Sources
- European Payments Council - 2025 SEPA Direct Debit Core Rulebook (accurate as of November 2026) https://www.europeanpaymentscouncil.eu/node/26581
- Bank of Ireland - Direct Debit Creditor Guide (accurate as of November 2026) https://businessbanking.bankofireland.com/app/uploads/4293010_3240302-Direct-Debit-Creditor-Guide-Apr23-V02-FA.pdf
- Citizens Information - Payment Services Directive (accurate as of November 2026) https://www.citizensinformation.ie/en/money-and-tax/personal-finance/eu-payments/psd2/
