Ask any email marketer about their biggest pet peeves and you’ll hear this – email lists contaminated with disengaged subscribers.
A disengaged list is problematic for two key reasons. First, it garners low email engagement rates. And second, it harms your email deliverability.
And if your engagement metrics have been limping for a while, your deliverability is probably already taking the brunt—even if you haven’t noticed it yet.
However, the good news is that you can enhance engagement through ongoing email marketing efforts.
So, what do you do about disengaged subscribers?
In this post, we’ll break down how a disengaged list hurts your deliverability and what you can do to bounce back.
Why Engagement Matters to Deliverability
Email Mavlers latest infographic, Email Trends and Insights, 2025, brings a renewed focus on email engagement and its impact on deliverability.
If you ask one thing email marketers need to wear on their t-shirts in 2025 (or at least tape onto their laptops), it’s this: Engagement = Deliverability. It’s not a hunch. Inbox providers today play by this rule, among the others.
Used to be times when inbox providers leaned heavily on basic filters to detect spams. Such as spammy keywords, high bounce rates, and complaint volume. But then, senders got smarter and spammers sneakier. The algorithms had to evolve.
Today, Gmail, Yahoo, and Outlook—all consider engagement levels, along with the other factors, to decide if your emails are wanted. Should they be delivered or tossed to the spam folder?
As more of your subscribers open, click, forward, or engage with your emails, inbox providers will likely see you as a reputable sender. A stronger sender reputation leads them to reward you with better inbox placement, i.e., the primary inbox, and not just Promotions or Spam.
On the other hand, disengaged subscribers are ignoring you or silently deleting your emails without even opening them. To Gmail’s algorithm, that’s an indication that the audience doesn’t find your email content relevant. And the future campaigns start getting filtered out as spam, even for subscribers who do want to receive your emails.
Translation: It’s a loop.
Good engagement → better deliverability → more inbox visibility
Poor engagement → lower deliverability → more emails unseen
So, an engaged email list is more than important if spam is the last place you want your emails to land in.
That’s more true now than ever, confirms Chris Behrens, founder of BearMail. He adds that inbox providers will soon go over sorting by date or tabs. They’ll start prioritizing emails based on an individual ‘s email engagement history with the sender. Meaning that even if your email gets delivered, it might not be visible near the top unless the subscriber has been opening your emails.
Which makes your job clear: fix the low engagement issues as soon as you notice them.
What Happens When Your List Is Full of Disengaged Subscribers
By now, you must have understood that disengaged subscribers aren’t just sheerly indifferent souls who have stopped interacting with your emails. They’re the ones dragging your sender reputation through the mud while taking up space you’re paying for.
But how do you know if a subscriber is truly inactive?
According to Kate Nowrouzi, Mailgun’s VP of Deliverability, there’s no hard number. But if a contact hasn’t interacted with your emails over 90 days, it might be time to take action. Why?
Because disengaged email addresses trigger a range of deliverability issues—
- Spam complaints. Subscribers who no longer wish to continue their subscription may report you as spam.
But to be a good sender your spam complaint rate should be well under 0.3%, says Marcel Becker from Yahoo. That’s because, Google and Yahoo sender requirements, 2024 sets the spam compliant threshold at 0.3%. Above which, you’re in the zone of being blocklisted.
Image Source: Mailgun
- Spam traps. Some inactive email addresses are used as spam traps to catch spammers. Sending to one, even by mistake, can damage your sender reputation and cause inbox placement issues.
- Hard bounces: Emails that hard bounce (when an address is invalid or inactive) is a symptom of compromised list health.
- Reputation damage: All of these snowball into a major blow to your sender reputation.
Good News Part 1: Engagement Can Be Reignited
Before you start scrubbing your email list like it’s biohazardous waste, take a breath.
Yes, a disengaged list hurts your deliverability. But by no means do you remove contacts the moment they stop clicking.
As Komal Helyer of Profusion CRM puts it: “Every subscriber is a potential source of revenue. So let’s not write them off just yet without a last attempt.”
She’s right. Those contacts signed up for a reason. They were interested once—maybe even excited. It’s best not to rashly give up on them.
Who knows if a subscriber who’s inactive on email might still be interacting with your brand on other channels? Clicking your ads, following you on socials, or walking into your store. Also, there’s the billboard effect: even unopened emails can drive awareness if the subject line’s strong enough.
That’s why Jeanne Jennings of Email Optimization Shop advises against a hard cutoff. Instead, she recommends reducing your email sending frequency for inactives. If sending daily, drop to weekly. Weekly? Try monthly. It’s a smart move on two fronts:
- You save money if you’re billed per send.
- You show respect for your subscriber’s inbox, which just might earn you a second chance.
Jeanne also suggests isolating inactive subscribers on a separate IP. That’s because these contacts carry a higher risk of spam complaints. You don’t want them dragging down your reputation with your active audience. Keep the risky traffic quarantined.
And, of course, you don’t just sit and hope they’ll come back. You reach out. A triggered re-engagement campaign is your best chance at winning them back. Or at least decide if the disengaged email address should be opted out of future emails.
Here’s what that looks like:
- Send a short series of automated emails targeting inactive subscribers who reach, let’s say, X days without opening or clicking.
- Revitalize their interest with incentives. Or something they might have forgotten. Imagine reward points, unused store credit, and a still-valid discount.
- Include a confirmation link to confirm if they’d like to continue getting your emails.
- As the final push, just ask. A quick one-question email, such as “What would you like to hear from us?” can give you a clearer picture than a flashy discount ever will.
Good News Part 2: You Can Clean Your List Without Losing Value
Too often, marketers consider cleaning email lists as the death of their marketing efforts. It’s not. Rather, it’s the start of smarter ones. 47.5% of marketers who clean their lists regularly say it helps them maintain strong deliverability.
Yet, almost 40% of marketers hardly ever conduct list hygiene. The longer you put list hygiene on hold, the more you’re inviting spam complaints, hard bounces, and plunging sender reputation.
So, how do you clean a list without missing out on potential engagement? Start with these foundational tactics:
- Remove hard bounces.
- Unsubscribe anyone who marks you as spam.
- Segment according to engagement levels and personalize your messaging (or frequency) to each.
- Implement a sunset policy. It sets specific benchmarks for unengaged behavior and moves those subscribers out of your active segment.
Important >> A healthy list starts with how you build it in the first place. To build an engaged list, stop relying solely on one-click sign-ups.
As Nick Schafer, Mailgun’s Sr. Manager of Deliverability & Compliance, says, double opt-ins help you build a more engaged subscriber base and act as a safety net against bot-driven signups.
Wrapping Up
An engaged, well-groomed email list is essential to have a good reputation with mailbox providers. And it’s not carved in stone. Treat list hygiene as a quarterly check-up. Remove invalid addresses, avoid spam traps, and monitor engagement metrics.
It’s no rapid-release pill. But when you follow best practices and track engagement, you’ll build a healthier list.
