Compliance at pre-bill (or pro forma) is too late
At one firm I spoke to, the bulk of the month's time arrives on the last day of the month. The pro formas go out the next morning.
It's less of a billing review process and more of a sprint finish.
Almost every firm treats the pre-bill (or pro forma) as the moment to catch potential guideline violations. It makes sense on paper: everything is in one place, the billing partner is looking, and nothing has gone to the client yet. In practice, it is the one moment when there is no time left to do the job properly.
The month-end squeeze
The pattern is remarkably consistent. At firm after firm, around half of the month's time is entered in the final week, and a good share of that on the final day. Lawyers are busy doing the work. Recording it comes later.
So the review window is not a month. It is a few days, sometimes a few hours, between the last entries landing and the pro formas going out. Any entries that arrive after the pro forma is run sit in limbo until someone regenerates it by hand.
One billing lead summed up their month-end as a weekend sprint whenever a big client's deadline fell at the wrong moment. Nobody I spoke to described it as relaxing.
What a pre-bill review can actually do
Now look at the volume. A single pro forma for a large matter can run to hundreds of entries from a dozen or more timekeepers. At one firm, partners each review 100 to 200 pre-bills a month. At another, a small team of attorneys works through thousands of them, one at a time. One firm still ships boxes of printed bills to partners' hotel rooms so they can review on the road.
And it isn't one job, it's dozens. Every client has its own guidelines and its own way of enforcing them, so the reviewer has to switch rulebooks with every pre-bill. Nobody can do that properly in a few days, so firms do the sensible thing. They triage.
The biggest clients and the ones with the strictest guidelines get a careful look. Everyone else gets a skim. And even the careful look is mostly a hunt for the obvious: block billing, vague narratives, the wrong rate. The subtler problems, like two lawyers billing for the same task or a client's unwritten rules, need context and time. At month end, there is neither.
The result is that pre-bill review catches what it can, for the clients it can, and hopes the rest gets through.
Late fixes cost more than early ones
When a problem is caught at pre-bill, there are only bad options.
Fix it, slowly. The narrative has to go back to the lawyer who wrote it three weeks ago, who now has to remember what they did and rewrite it while billing waits. Multiply that by every flagged entry.
Write-down. Often the quickest way to get the bill out is simply to cut the time. That's revenue the client might well have paid for, if the entry had been recorded properly in the first place.
Let it through. Then the client's reviewer finds it instead. The invoice is rejected or reduced, the appeal starts, and a payment cycle that should take 30 to 60 days stretches past 90.
And because each fix happens in a rush, nothing is learned. The same lawyer writes the same entry next month, and the billing team faces another deluge in a few short days.
Move compliance upstream
But fear not, there is a better way.
The firms making progress have stopped treating the pre-bill as the review point. Instead, they've moved the work upstream: each entry is checked as soon as it hits the practice management system.
The work spreads across the month. Instead of thousands of entries in a few days, the billing team deals with a steady trickle. One firm I spoke to wants every entry reviewed within 48 to 72 hours of the work being done.
The right person fixes the right problem. Simple issues, like task codes or a missing detail, are handled by billing straight away. Only the entries that genuinely need legal context go back to a lawyer, while they still have the context.
Every client gets the same scrutiny. When review isn't squeezed into a few days, there's no need to triage. The mid-sized client with fussy guidelines gets the same attention as the largest one.
Pre-bill becomes a final check, not a cleanup. Which is what everyone already pretends it is.
None of this is possible if checking every entry depends on a person reading it. It needs technology doing the first pass, so people can spend their time on the entries that actually need judgment.
Three questions to ask your team this week
What share of last month's time was entered in the final week?
Which clients' pre-bills got a full review last month, and which got a skim?
When a problem is found at pre-bill, how often is it fixed, and how often is it just written down?
If the answers make you wince a little, you're not alone. Elite's 2025 Revenue Cycle Management Survey found that 71% of firms still rely mainly on manual processes for guideline compliance. The good news is that the fix isn't working harder at month end. It's doing less of the work there.
If you're wrestling with this at your firm, I'd be glad to compare notes. Ideally not on the last day of the month.
This is the second in a short series on where law firm revenue leaks between time entry and payment. The first looked at why billing controls don't work.
Next: The unwritten Outside Counsel Guidelines.
