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Every unbilled hour on your files has a practical expiry. The work was real, the value was real, but the longer that time sits as work in progress the more it fades, first in the client's memory, then in yours, and eventually in what you feel comfortable charging for it. There is no warning when WIP goes stale. It just becomes money you will never see.
Most billing advice tells you to bill on time. Fine. But nobody misses a billing cycle on purpose. Time slips because reviewing and releasing bills is fiddly, interruptible work that never feels urgent until month end, and by then a third of the file is already stale. The fix is not willpower. It is a small, boring routine that runs every week whether you feel like it or not.
Why WIP Quietly Becomes Money You Never See
Think about a docket entry from eleven weeks ago: a phone call, some research, a revised draft. When you finally look at it to bill, three things happen. You cannot fully reconstruct what you did, so the narrative gets vague. Vague narratives get discounted, either by you before sending or by the client after receiving. And because the matter has moved on, raising a bill for old work feels like reopening a closed chapter, so you shave it "to keep the relationship smooth."
None of that happens if the same entry gets billed within a fortnight. The write-down on aged WIP is not a line item anyone plans for, which is exactly why it does so much damage. It is the difference between the time you recorded and the money that reaches your trust or general account, and it compounds silently across every open matter.
Warn. Aged WIP also muddies your realization picture. If you only measure what you collected against what you invoiced, you never see the hours that quietly evaporated before they became an invoice at all.
A Fifteen Minute Friday Review That Catches Everything
Pick a fixed slot. Friday late morning works for most people, because you still have the week fresh and you are not yet in weekend brain. Block fifteen minutes in your calendar and treat it like a hearing you cannot move. The goal is not to bill on Friday. The goal is to look at every matter with unbilled time and make one decision per file.
Sort your open matters by the age of their oldest unbilled entry, oldest at the top. Then go down the list and assign each file to one of four buckets:
- Ready to bill. The work is done or a natural milestone has passed. Draft the bill now or flag it for the batch.
- Needs a note. A docket entry is thin or missing. Fix the narrative while you still remember what happened.
- Hold with a reason. You are genuinely waiting on something, so write down what and until when.
- Problem. The retainer is low, there is a fee dispute brewing, or the client has gone quiet. Escalate today, not at month end.
Fifteen minutes is enough because you are triaging, not drafting. Most files take ten seconds. The two or three that need real attention are exactly the ones that would have rotted into a write-down if you had waited.
Batching Draft Bills So Nothing Slips a Cycle
Drafting bills one at a time, scattered through the week, is how work slips. Context switching kills it: you open a file, get pulled into an email, and the half finished bill sits for days. Batch instead. Once your Friday review has flagged the "ready to bill" files, set aside one focused block, later that day or first thing Monday, and draft them all in one pass.
When you are already in billing mode, the narratives come faster and read more consistently, which clients notice. You catch the file where three small entries should be described as one coherent piece of work. And you finish with a clean stack of drafts sitting in one place, waiting for review, instead of scattered across the week and half-remembered.
Tip. Keep a short, plain-language phrase bank for common tasks so recurring work reads clearly and consistently. It speeds drafting and it heads off the "what is this charge?" email before it lands.
If your system lets you draft bills straight from unbilled time, use it. Pulling the docket into a draft in one step is the whole point of running Time & Billing and Invoices in the same place, and it is where a tool like A1 CMS earns its keep on a busy Friday.
Setting Age Limits That Trigger Action Automatically
A routine you have to remember is a routine you will eventually forget. Give WIP a maximum age and make crossing that line trigger something you cannot ignore. A workable default for many practices:
| Age of oldest unbilled time | What it means | Action |
|---|---|---|
| 0 to 14 days | Fresh, healthy | Normal weekly review |
| 15 to 30 days | Getting stale | Bill this cycle, no exceptions |
| 31 to 60 days | At risk | Draft now and note why it aged |
| Over 60 days | Likely write-down | Escalate and decide: bill, discount, or defence of the number |
Numbers are a starting point, not gospel. A litigation file that bills at milestones will breathe differently from a steady solicitor's retainer. The point is to name a threshold out loud so that aging is a visible event, not a slow surprise you meet at year end.
The write-down on aged WIP is the money you decided not to chase, one quiet Friday at a time. A hard-earned billing lesson
Handing Off Review Without Creating a Bottleneck
In most firms one person, a partner or the office manager, signs off before a bill goes out. That is sound. It also becomes the exact spot where clean drafts go to die, because the reviewer is the busiest person in the building and the drafts pile up waiting for a spare hour that never comes.
Make the handoff cheap. Deliver drafts in one batch, not a trickle. Flag only the ones that genuinely need judgment, a large discount, a sensitive client, an unusual disbursement, so the reviewer can approve the routine ones quickly and spend real attention where it counts. Agree a turnaround, say drafts in Friday, approvals by Tuesday, so nobody is guessing. And when a bill sits too long in review, treat that as its own aging problem, because a draft stuck in approvals is still WIP quietly getting older.
Note. If the reviewer is your constraint, protect their time, do not add to it. A tidy weekly batch with clear flags is a gift. Ten random drafts a day is a tax.
Start This Friday
You do not need a new billing philosophy. You need fifteen minutes on Friday, a batch block to draft, an age limit that forces a decision, and a handoff that does not clog. Do that for a month and the change shows up in two places: fewer aged entries at month end, and a smaller gap between the time you recorded and the money you actually collected. For more on tightening the same loop, see our pieces on a calm month-end close and what realization and utilization really tell you.
