We looked at 4,024 invoice follow-ups. Here is when clients actually pay.

Across 1,580 invoices that Reeve followed up on and that were then paid, the median time from the first reminder to payment was 14 days. The median invoice needed exactly one touch. 74% were paid within 30 days of the first email. And 19% of what was recovered was more than 90 days past due by the time it was paid, which is to say: the invoices everyone had given up on were still collectible.

These are aggregate numbers from the first two businesses to run Reeve at volume, with demo and sample accounts excluded. Two businesses is a small sample and we say so; it is also 4,024 real follow-ups and $654,000 of real recoveries, which is more than most advice on this topic is based on. No client, invoice, or business is identifiable here. We will update the post as the sample grows.

What is in the sample?

• 1,580 invoices that were paid after at least one Reeve follow-up went out, across two B2B service businesses on QuickBooks Online.
• 4,024 follow-ups sent in total, in the sender's own name from their own email account, escalating in tone over time.
• $654,068 recovered on those invoices.
• Excluded: demo accounts, invoices paid before any follow-up was sent (those are not recoveries), and follow-ups that were drafted but never sent.

One caveat up front. Both businesses are B2B, both chose to use a follow-up tool, and one of them came to Reeve with a large backlog of aged invoices, which shapes the age numbers below. Treat these as what consistent follow-up produces on a real book, not as what happens on its own.

How fast do clients pay after the first reminder?

The distribution is front-loaded. 35% of recovered invoices were paid within a week of the first email, and 50% within two weeks. The long tail is real but thin: only a quarter took longer than a month. If a reminder is going to work, it usually works fast, which is the strongest argument for sending the first one the day after the due date rather than three weeks later.

How firm does the message have to be?

Reeve escalates in tone: a friendly or direct opening note, a firm follow-up if that goes unanswered, and an escalation step that copies a decision maker. For each recovered invoice we looked at the firmest message that had been sent when the payment landed.

The median recovered invoice needed exactly one touch. Two readings of this table, both true: most overdue invoices are not refusals, they are lapses, and a single specific, polite email fixes four in five of them. And the firmer messages are not wasted; the one in five that needed them are the invoices that would otherwise have become write-offs.

What is a reply worth?

27.5% of all follow-ups got a reply. That rate drops as the tone firms up, which is the opposite of what most people expect:

40% of recovered invoices had at least one reply from the client before payment. A reply is not payment, but it is the moment the invoice stops being invisible. In practice most replies are one of three things: 'it is in our queue,' 'we never got this,' or a question about the invoice. All three are solvable in a day, and none of them happen if nobody sends the email. The falling reply rate at firmer tones is worth sitting with: the clients who are going to engage mostly engage early. Firmness is for the ones who will not, and its job is payment, not conversation.

When is the best time to send a payment reminder?

We looked at reply rates by send time and send day. Reminders sent during the US afternoon got replies 29% of the time, morning sends 28%, and overnight sends 15%. By day of week, Wednesday and Thursday sends did best at 33%, Monday and Tuesday came in at 27%, and Friday trailed at 23%.

The business-hours gap is the only large one, and it mostly says: do not send at 3 a.m. Midweek beats Friday by ten points, which is worth having, but every one of these gaps is smaller than the gap between sending consistently and not sending at all.

What day do clients pay?

Payments cluster at the edges of the week: Tuesday (24% of recoveries), Friday (23%), and Monday (22%), with Wednesday and Thursday trailing at 16% and 14%. That lines up with how most AP departments batch their runs, early in the week or end of week. Combined with the reply data above, a midweek send lands in the inbox before the next payment run rather than just after it. If your reminder arrives the day after a client's run, it waits a week regardless of how well it is written.

How old can an invoice be and still get paid?

The median recovered invoice was 32 days past due when it was paid. 27% were more than 60 days past due; 19% were more than 90. One of the two businesses in the sample came to Reeve with a deep backlog, so these age figures run higher than a book that has been worked consistently would show. But that is the point: the backlog paid. These were invoices that had stopped getting any attention, and a meaningful share of them paid within weeks of a fresh, specific, human-sounding email. Age is a reason to follow up, not a reason to stop.

The invoice is not dead. It is just not on anyone's list. A follow-up puts it back on the list.

What to do with this

• Send the first reminder the day after the due date. Half of what gets paid, gets paid within two weeks of the first email. Waiting costs you the fast payers.
• Escalate on a schedule, and finish the sequence. One in five recoveries needed a firm or escalated message. Those are the write-offs that did not happen.
• Send midweek, during business hours. Wednesday and Thursday sends got a third more replies than Friday sends.
• Answer replies the same day. A reply is the invoice becoming visible again. Do not let it go dark twice.
• Go back for the old ones. Nearly one in five recoveries in this sample was over 90 days past due. The oldest was 651.

Reeve does all of that automatically for businesses on QuickBooks Online, in the owner's name, and these numbers are what that looks like on the first two books it ran at volume. We will update this post as the sample grows.