Accounts Receivable for Accounting and Advisory Firms

Bookkeeping, accounting, legal and advisory firms get paid late mostly because billing trails the work and nobody wants to be the person who chases a client. Invoices go out in month-end batches, hourly bills arrive larger than the client expected, and follow-up waits until a partner has time. The fix is billing on a fixed rhythm, invoices that answer every question up front, and polite follow-up that runs on schedule so the advisor never has to make the awkward call.

Professional services firms average about 43 days of DSO, with a typical range of 30 to 58 days, and the firms sitting at 55 days or more are usually the ones without automated follow-up after the invoice goes out (Credit Pulse DSO benchmarks, citing the Credit Research Foundation). Across US B2B credit sales, 43% of invoice value was overdue in 2025 (Atradius, 2025). In a firm that sells time, every one of those days is payroll already paid for work the client already has.

This page covers how bookkeeping practices, accounting and tax firms, fractional CFO and advisory firms, and legal practices actually bill, why their receivables run long, and how follow-up should work when the client is also a relationship you want to keep for years.

Most firms run several billing models at once, and each one stalls in its own way. Knowing which model an invoice came from tells you what kind of follow-up it needs.

Monthly fixed fees and retainers

Bookkeeping, payroll support, outsourced accounting and fractional CFO work usually bill a fixed monthly fee. When it is billed in advance and paid by card or bank debit, this is the fastest-paying model a firm has. When it is billed in arrears and paid by cheque, it quietly drifts a cycle behind.

Hourly and time-based billing

Advisory projects, consulting and legal matters often bill by the hour. The longer the gap between invoices, the larger and more surprising each invoice becomes, and a surprising invoice is an invoice that gets questioned. Weekly or biweekly billing keeps each amount small and easy to approve.

Project and seasonal engagements

Cleanups, catch-up bookkeeping, year-end work, tax returns and audits are often priced per engagement and billed at the end. Seasonal work creates a wave of invoices at once, right when the team has the least time to follow up on them.

Unbilled work in progress

Accounting and legal firms carry a second receivable that never appears on the aging report: hours worked but not yet billed. Firms often track lockup, which is unbilled work plus unpaid invoices, because DSO only starts counting once the invoice exists. Our guide to getting clients to pay on time walks through a lockup example and a billing model comparison in more depth.

Most late payments in accounting and advisory firms come from billing habits and from follow-up that depends on someone remembering, not from clients who will not pay. Four causes account for most of the delay.

Billing waits for month-end

Partners and staff are busy doing billable work, so invoices go out in one batch at the end of the month. Every week an invoice waits to be sent is a week added to the firm’s collection time before the client has done anything wrong.

The advisor does not want to ask

Asking a client about money can feel at odds with being their trusted advisor. So the follow-up gets softened, delayed, or skipped entirely, and the clients who pay slowest learn that nothing happens when they do.

The invoice raises more questions than it answers

An hourly invoice with vague descriptions, no reference to the engagement, or an amount well above the last one invites a question. The client does not dispute it. They simply wait until they have time to ask about it.

Small invoices never get chased

A bookkeeping practice with a few hundred monthly clients has a long tail of small balances. The large clients get a call. The rest age quietly until the year-end cleanup.