A single postcard is a coin flip — it might catch the right person on the right day, or it might land in the recycling bin during a busy week. Multi-wave campaigns turn that coin flip into reliable response. By sending the same recipient 2–3 different cards over 6–10 weeks, you compound exposure, fight forgetting, and reach people in different mental states. This guide explains how waves work in PostKnock, the recommended timing, and when to use two waves vs three.
What Is a Wave?
In PostKnock, a campaign is the overall outreach effort — for example, "Q3 Lapsed Patient Recall." Each campaign is made up of one or more waves. A wave is a single mailing event with its own postcard design, message content, scheduled drop date, and (optionally) a follow-up phone script.
Every contact in the campaign moves through every wave in order. If a contact responds (books an appointment, scans the QR, calls in) before the next wave drops, you can mark them "responded" and they're automatically excluded from the rest of the sequence. The system keeps mailing to non-responders only.
A wave is also where channels combine. PostKnock waves are omnichannel by design — you can attach a postcard, a follow-up call (Pro only), and (eventually) email or SMS to the same wave so they fire as a coordinated unit.
Recommended Timing Between Waves
After thousands of campaigns across our customer base, the timing that produces the best response rate is:
- Wave 1: Day 0 (drop date)
- Wave 2: ~28 days later (4 weeks after wave 1)
- Wave 3: ~28 days after wave 2 (8 weeks total)
Why 28 days? It's long enough that the first card has been seen, processed, and either acted on or set aside — but short enough that the recipient still associates wave 2 with wave 1. Sequences shorter than 3 weeks often feel pushy. Sequences longer than 6 weeks lose the cumulative-touch effect.
For seasonal or insurance-window campaigns (e.g., "use your benefits before Dec 31"), you can compress to 2–3 weeks between waves to fit inside the window. Just expect slightly lower response per wave because there's less recovery time.
When to Use 2 Waves vs 3 Waves
Use 2 waves when:
- Your contact list is small (under 200 people) and you want to keep total cost down.
- You're testing a new offer or message and want to see the response curve before committing more spend.
- You're operating in a tight time window (insurance reset, seasonal sale).
- The campaign goal is awareness, not conversion (e.g., announcing a new service location).
Use 3 waves when:
- You're running patient recall or customer reactivation. The cumulative response advantage is worth the extra cost — usually pays for itself many times over.
- Your average customer lifetime value is high (over $500). The extra wave costs cents per contact but recovers a customer worth hundreds.
- You have an active call queue and want each wave to feed the calling team a fresh batch of warm prospects.
Single-wave campaigns get a 3–5% response rate. Three-wave campaigns commonly hit 8–12% cumulative response. The marginal cost per added wave is small, the marginal lift is large. For more on the response math, see our blog post on postcard marketing ROI.
Designing Different Cards Per Wave
A common mistake is using the same postcard for every wave. The recipient sees what looks like a duplicate and thinks "I already got this one" without reading. To get the cumulative-touch effect, each wave needs to look different at a glance.
A simple pattern that works:
- Wave 1 — Warm tone. Friendly headline ("We miss you, Sarah!"), photo of the team or office. Soft offer.
- Wave 2 — Different design, stronger offer. Different hero photo, alternate color emphasis, sharper headline. Increase the offer value or add personalization.
- Wave 3 — Urgency. Deadline-driven design ("Last chance before April 30"). High-contrast colors. Clear final call to action.
PostKnock makes this easy: each wave references its own design from your library. You can build all three designs once, save them, and reuse them every time you run the same playbook. For best practices on the design side, see Customizing Your Postcard Design.
The 90-Day Rest Cycle
After a multi-wave campaign completes, contacts who didn't respond are placed on a 90-day rest cycle. During those 90 days, they will not receive postcards from any other PostKnock campaign you run. This protects you from over-mailing the same household and keeps response rates from decaying due to fatigue.
Once the 90 days are up, contacts are eligible to be enrolled in the next campaign automatically. The rest cycle is enforced by PostKnock's contact engine, so you don't have to track it manually. If you have a true emergency need (a critical announcement to your whole patient base), you can bypass the rest cycle on a per-campaign basis — but you'll see a warning before launch.
Free vs Pro: Multi-Wave Features
Multi-wave behavior differs by plan:
- Free plan — Single-wave postcard campaigns. Per-card rate $1.05. No follow-up call queue. Great for one-off promotions or your very first send.
- Pro plan ($99/mo) — Up to 3 waves per campaign. Per-card rate $0.79. Follow-up call queue activated automatically 3–5 days after each wave's expected delivery. Sequence templates ("playbooks") with pre-tuned timing and copy.
For most service businesses with a customer list bigger than 100, Pro pays for itself within the first campaign. The combined savings on per-card rate plus the lift from multi-wave plus the call queue typically delivers 3–5x the response of a single Free-plan send. See How PostKnock Pricing Works for the cost math.
Common Wave Mistakes
- Same design for every wave. Looks like a duplicate, gets ignored. Always vary the look.
- Waves too close together. Less than 3 weeks feels intrusive and lowers response.
- Waves too far apart. More than 6 weeks and the cumulative effect fades.
- Forgetting to mark responders. If your front desk doesn't update the contact when someone books, you'll keep mailing them. Use the call queue or contact-detail page to mark responders so they exit the sequence.
If you're building a recall sequence for a dental, optometry, or vet practice, the timing principles in our patient recall best practices guide apply directly to PostKnock waves.
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