Latest / The Email Marketing Podcast with Fexingo: Newsletters, Open Rates, and Subscriber Growth / Why Email Frequency Capping Boosts Retention
Transcript
- Lucas: Let me start with a number that stopped me this morning. According to a 2025 Litmus benchmark report, the average marketing email list loses about 22 percent of its subscribers every year — not to spam complaints, just people hitting unsubscribe because they're getting too much email. Luna: Twenty-two percent? That's huge. And I bet the send frequency is a big piece of that. Lucas: It is. And yet most brands still send on a fixed schedule — every Tuesday and Thursday, or five emails a week — without ever asking if that's what the subscriber actually wants. Today I want to talk about a fix that's surprisingly straightforward: frequency capping. Luna: Define that for someone who's new to the term. Lucas: Sure. Frequency capping means setting a hard limit on how many emails a specific subscriber can receive in a given time window — per day, per week, or per month. You don't just blast the whole list. You let engagement data decide the pace. Luna: And the alternative is basically treating every subscriber like they want the same amount of email. Lucas: Exactly. Which is absurd. Some people on your list opened yesterday and clicked through. Others haven't engaged in six months. Why would you send both groups the same number of messages? So frequency capping is really about respecting attention. Luna: Is there a good case study you've seen recently? Lucas: Yeah, there's one from a mid-size DTC brand called Rove — they sell travel accessories. Their marketing team noticed that unsubscribe rates spiked every time they added a third email in a week. So they tested capping at three per week instead of five. The result: unsubscribe rate dropped 40 percent, and open rates climbed from 18 percent to 30 percent in six weeks. Luna: That's a twelve-point jump in open rate. And it's probably because the remaining emails felt less like noise and more like signals worth opening. Lucas: Right. And that's the behavioral science bit — there's a concept called 'scarcity of attention.' When you know you'll only get a few emails from a brand, you're more likely to open each one. Rove's data backs that up. They also saw click-through rates improve by about 8 percent. Luna: So the cap itself is simple, but implementing it — how do you decide what the cap should be? It can't be one-size-fits-all. Lucas: It shouldn't be. The best approach is tiered caps based on engagement. Your most active subscribers — those who opened in the last 7 days — might handle four or five emails a week. Your medium-engaged group — opened in the last 30 days — gets two or three. And the dormant group, the ones who haven't opened in 90 days, maybe one email a week at most, or even a re-engagement sequence instead of a cap. Luna: That makes intuitive sense, but I wonder how many brands actually do that. My sense is most small teams just set and forget their send cadence. Lucas: That's the norm, yeah. Most email service providers make it easy to schedule sends but don't nudge you to cap. But the tools do exist. Klaviyo has a frequency rule engine where you can set per-profile limits. Mailchimp has send-time optimization that can also spread out sends. Even HubSpot lets you cap by lifecycle stage. The problem is rarely the tool — it's the mindset. Luna: And I imagine there's a risk of going too far in the other direction. If you cap too aggressively, you might miss revenue from people who actually want more email. Lucas: That's a real concern. You don't want to starve your best customers. So the key is testing and monitoring. Rove, for example, started with a blanket cap of three per week for everyone, then gradually relaxed it for the top decile of clickers. They tracked revenue per email sent and saw it actually went up because each email was more targeted. Luna: So the same number of emails, just spread smarter. Lucas: Exactly. And here's a nuance people miss: frequency capping isn't just about the total count — it's also about the spacing. Sending two emails on the same day can feel like spam even if you only send two that week. So some platforms let you set a minimum gap between sends, like at least 48 hours. Luna: I've definitely unsubscribed from brands that send multiple emails in one day. It feels desperate. Lucas: It does. And the data shows that those same-day double sends often have the lowest click-through rates. So it's not just about capping the volume; it's about pacing. Now, there's also a compliance angle. The can spam Act doesn't mandate frequency limits, but some countries like Canada's CASL and Europe's GDPR indirectly require you to respect subscriber expectations. If you promise a weekly newsletter and send five, that could be seen as misleading. Luna: Right, because consent is tied to the frequency the subscriber agreed to at sign-up. Lucas: Exactly. So there's a legal reason to cap too. But let's talk about the practical implementation. If you're listening and you want to test frequency capping this week, here's a simple framework. First, pull your list and segment by engagement recency — last 7 days, 8-30 days, 31-90 days, and 90-plus. Second, assign a weekly cap to each segment: say five, three, two, and one. Third, run it for four weeks and compare unsubscribe rate, open rate, and revenue per subscriber against the previous four weeks. Luna: That's a clean A-B test — the old schedule vs. the capped schedule. And I'd bet most brands see a net positive. Lucas: Most do, yes. But there's a counterintuitive risk: if you cap too low, you might actually increase unsubscribes from your most engaged users because they feel starved. So you need to watch your top-decile segment separately. If their engagement drops, raise their cap. Luna: Which brings up a good point — frequency capping isn't a set-it-and-forget-it tactic. It's an ongoing optimization. Lucas: Exactly. And one more thing — combine frequency capping with preference centers. If you give subscribers a way to choose their own frequency — weekly digest, daily updates, or only when there's a sale — you get even better results. A 2024 study by Email on Acid found that brands with preference centers had 25 percent lower churn than those without. Luna: That stat makes sense. People like control. And if they can choose three emails a week instead of five, they're more likely to stay. Lucas: Right. And that ties back to the scarcity principle — when people choose to receive less, the emails they do get feel more valuable. So the takeaway is: don't assume your current send cadence is optimal. It's almost certainly too high for a big chunk of your list. Luna: Alright, I'm going to try this on my own newsletter this month. But before we wrap, Lucas — you mentioned the Litmus benchmark earlier. What's the concrete action step for someone who wants to start today? Lucas: Log into your email service provider, find the send frequency settings, and set a temporary cap at three emails per week for everyone. Run it for two weeks. Compare your unsubscribe rate and open rate to the two weeks before. If you see improvement — and you probably will — then start segmenting. It's that simple. Luna: And if it doesn't improve, you can always go back. No harm in testing. Lucas: Exactly. And that's the beauty of email marketing — everything is testable. So test your frequency cap this week. Luna: Great advice. That's all for today — go cap your list and see what happens.