A scrub isn't a certificate. It's a photograph. It tells you the DNC and litigator status of every number on your list at the moment you ran it — and the moment you close the file, the picture starts going stale. People file DNC complaints. Numbers get reassigned. A contact who was clean in January registers on a state list in February, or files their first TCPA suit in early March, and now they're a landmine your last scrub never saw.
Full disclosure: I work for Ready, and we sell standalone TCPA/DNC litigator scrubbing at $0.005 per contact. So I have a reason to tell you to scrub more. But the honest version isn't "scrub everything every week" — that's just burning money. The honest version is that different list sources rot at different speeds, and the right cadence depends on where the list came from and how old it is. Let me show the math.
Why a scrub decays at all
Three things change under a static list:
- New DNC registrations. People add their numbers to the federal DNC and to state registries continuously. A clean number today can be registered next week.
- New complaints and litigator activity. Someone files their first complaint, or a known serial plaintiff picks up a reassigned number. Litigator databases update as new cases surface.
- Number reassignment. Carriers recycle disconnected numbers. A 12-month-old list is roughly 30% reassigned or disconnected numbers — and the person who now holds that number never consented to anything.
None of these are on your side. They all move a clean number toward dirty. Which is why the DNC scrub effectively expires — most compliance teams treat federal DNC results as good for about 31 days, because that's the registry's own recommended refresh window.
Rot speed depends entirely on the source
Not all lists decay at the same rate. A list you grew — real opt-ins, freshly collected — is close to its cleanest state and drifts slowly. A list you bought or skip-traced was never clean to begin with, and the numbers on it are older, more recycled, and statistically loaded with people who've complained before.
The data pattern most operators eventually confirm on their own lists:
- Purchased lists flag around 5x more litigators than opt-in lists on the first scrub — see the source-based hit-rate breakdown.
- Aged lists compound it. A list you bought 8 months ago carries roughly 3x the litigators it did on day one, because the numbers keep aging and getting reassigned to people you never vetted.
So the two variables that drive cadence are source (how dirty it started) and age (how fast it's drifting).
The cadence table
Here's the schedule I'd actually run. Treat "re-scrub" as re-running the full DNC + litigator scrub against the current list.
| List source | Starting risk | Re-scrub cadence | Why |
|---|---|---|---|
| Opt-in, actively growing | Low | Rolling — scrub new contacts at intake, full list every 30 days | Fresh consent, slow drift; the 31-day DNC window is your governing constraint |
| Opt-in, dormant 3+ months | Medium | Every 30 days + before any re-engagement blast | Consent ages, numbers reassign; scrub before you re-contact |
| Skip-traced | Medium-high | Every 2–4 weeks while in active dialing | No consent baseline, high reassignment rate; line-type churn is real |
| Purchased / rented | High | Before every send, or every 14 days minimum | Highest litigator density, oldest numbers, worst reassignment — this is the TCPA time bomb |
The source-based scrub schedule post goes deeper, but the headline is simple: a bought list needs scrubbing roughly 3x more often than one you grew.
The cost math, worked out
This is where teams talk themselves out of frequent scrubbing — and where the numbers actually make the opposite case.
Say you're running a 50,000-contact purchased list. Scrubbing at $0.005/contact:
- One scrub: 50,000 × $0.005 = $250
- Every 14 days, for a year (~26 scrubs): $6,500/year
That feels like a lot until you put it next to the downside. A single TCPA complaint runs $500 to $1,500 per text. On a dirty purchased list, missing even one newly-registered litigator on a 50,000-message blast is a plausible event — and one plaintiff who's filed before will happily turn a single text into a demand letter. Scrubbing 100,000 contacts costs $500; one complaint costs $500 to $1,500 per text. The whole year of re-scrubs costs less than a single mid-range settlement.
Now the opt-in list, same size, on a 30-day cadence:
- One scrub: $250
- 12 scrubs/year: $3,000/year
Half the spend, because the list drifts slower and doesn't need the 14-day pace. That's the point of matching cadence to source — you spend where the risk is instead of scrubbing everything at the highest frequency.
Scrub, then re-engage — in that order
One sequencing mistake wastes real money: re-engaging an aged list before you scrub it. If a 12-month list is 30% dead numbers, and you blast first, you're paying to text disconnected lines and reassigned strangers — and every reassigned number is a fresh consent problem. Scrub first, suppress the matches and dead numbers, then send to what's left. The scrub-then-reengage order is the cheaper path in both directions: less wasted SMS spend and less exposure.
For an opt-in list that's been dormant, the same rule applies with less urgency — scrub before the re-engagement send, not after.
What the scrub actually catches (and what it doesn't)
Two clarifications so you set expectations correctly:
- A litigator flag isn't "never contact." It means this specific person has a history of suing over texts. You suppress them because the cost/benefit is lopsided, not because contacting them is illegal by default.
- DNC and litigator lists are different lists. A number can pass the DNC and still sue you — and there are actually three separate lists compliance teams confuse: federal/state DNC, your internal do-not-call, and known-litigator databases. A good scrub checks all of the ones a machine can check; your internal opt-out list is on you to maintain.
And no scrub makes you lawsuit-proof. Consent is the foundation, quiet-hours enforcement reduces exposure, and scrubbing is the third layer — the three layers of TCPA risk reduction work together, not in isolation. In Ready, quiet-hours enforcement and automatic STOP handling run on the platform; the standalone scrub is the piece you point at the list before you send.
The practical takeaway
Set cadence by source, not by calendar convenience:
- Grown, opt-in list: scrub new contacts at intake, full list every 30 days.
- Skip-traced: every 2–4 weeks while actively working it.
- Purchased or rented: before every send, or every 14 days at the outside — and expect the highest hit rate.
- Any aged or dormant list: scrub before you re-engage, never after.
At $0.005 a contact, the entire year of scrubbing a 50,000-contact list costs less than a single TCPA settlement. The expensive mistake isn't over-scrubbing — it's trusting a January photograph in March.
If you want to run a scrub against your current list without wiring up a full send, standalone TCPA/DNC litigator scrubbing at $0.005/contact is on Ready's product page, and you can start with 2,500 free credits to test the workflow before you commit a budget.