Email marketing best practices for unengaged subscribers: opt-out, suppression, or re-engagement?
Matthew Whittaker
Co-founder & CTO, Suped
Published 20 Apr 2025
Updated 19 Aug 2025
9 min read
Managing unengaged subscribers is a critical aspect of email marketing that directly impacts deliverability and sender reputation. It's a common challenge to decide whether to re-engage, suppress, or fully opt out subscribers who no longer interact with your emails. The choice isn't always straightforward, as it balances the potential for future engagement against the risks of damaging your email program.
Sending emails to an inactive audience can lead to lower open rates, higher spam complaint rates, and potentially getting your IP or domain listed on an email blocklist (or blacklist). These negative signals tell Internet Service Providers (ISPs) that your emails might not be valuable, which can lead to more of your messages landing in the spam folder instead of the inbox. This is why a clear strategy for handling unengaged subscribers is essential for maintaining a healthy email list and strong email deliverability.
We need to determine what constitutes an unengaged subscriber and then apply best practices to either win them back or remove them from our active sending lists. My goal is always to optimize for long-term deliverability and subscriber health, even if it means sacrificing short-term list size.
Identifying unengaged subscribers and their impact
Before deciding on a course of action, it's crucial to define what unengaged means for your specific email program. This definition will vary based on your sending frequency, content type, and business model. For many, an unengaged subscriber is someone who hasn't opened or clicked an email in a certain timeframe, such as 90 days, six months, or even longer, like nine months or 18 months, depending on the business context.
Sending emails to unengaged recipients can significantly harm your sender reputation. ISPs, including Google and Yahoo, closely monitor how subscribers interact with your emails. Low engagement signals, like consistent non-opens or deletions without opening, suggest that your content isn't relevant to recipients. This can lead to a decline in your sender score, increasing the likelihood of your emails being flagged as spam for all recipients, even those who are engaged. It's a key reason why many email experts emphasize retaining an email list mostly comprised of recently engaged subscribers.
Furthermore, unengaged subscribers are more likely to mark your emails as spam, inadvertently become spam traps, or simply never open your messages, leading to wasted sending volume. These factors contribute to a poor email deliverability rate and can even result in your domain or IP being added to a public or private blacklist, severely impacting your ability to reach any recipient.
My general rule is to focus on quality over quantity. A smaller, highly engaged list will always outperform a large list with many unengaged subscribers in terms of deliverability and overall ROI. It also prevents legal issues, especially if you're dealing with regulations like GDPR in Europe, where you might need to delete personal data if there's no re-engagement.
The re-engagement campaign approach
A re-engagement campaign is often the first step I recommend for unengaged subscribers. This is a targeted series of emails designed to win back their attention and encourage them to interact with your brand again. The goal is to prompt them to explicitly confirm their interest in receiving future communications or to update their preferences.
A typical re-engagement sequence usually consists of 2-4 emails sent over a period, perhaps a few weeks or a month. These emails should be distinct from your regular marketing messages. They might include:
Clear subject lines: Indicating the email is about their subscription status, for instance, "Do you still want to hear from us?".
Value proposition: Reminding them of what they're missing or the benefits of staying subscribed. This could involve highlighting new features, exclusive offers, or helpful content. Offer an incentive such as a discount or free resource, to encourage interaction, as suggested by Mailpoet.
Strong call to action (CTA): Making it easy for them to opt-in again, update preferences, or visit your site. This is particularly important for emails you send out before removing unengaged subscribers from your list, as highlighted by Sharpspring.
Preference center link: Offering more granular control over what emails they receive, allowing them to adjust frequency or topics instead of a full opt-out. This can help you avoid spam traps.
When to send these campaigns depends on your engagement definition, but commonly they are triggered after 6 to 9 months of no activity. For ecommerce companies, this might even extend to 18 months, as the buying cycle could be longer.
Opt-out vs. suppression: the core dilemma
After a re-engagement campaign, if a subscriber still doesn't respond, the critical decision becomes: opt them out or suppress them?
Opting out means completely removing them from your active mailing list. To receive emails again, they would need to manually re-opt-in. This is the most conservative approach from a deliverability standpoint, as it ensures you only send to truly interested recipients.
Suppression, on the other hand, means preventing them from receiving marketing emails but keeping their data, allowing for potential re-engagement if they show interest through other channels, like making a purchase or engaging with a transactional email. This is where the dilemma often arises: Is opening a shipping confirmation or an abandoned cart email truly a signal of rekindled marketing interest, or merely a necessary interaction?
My preference is generally to err on the side of caution and opt them out. This forces a clear re-opt-in if they want to rejoin your marketing communications. While suppressing them might seem like keeping an option open, it risks sending unwanted marketing emails if their rekindled interest isn't a clear signal for marketing content. A true re-engagement should be explicit. If they come back and make a purchase, it's best to ask them if they want to opt-in again during that process, rather than automatically adding them back to a marketing list.
Opt-out (Sunset Policy)
Process: Permanently removes subscribers who fail to re-engage after a win-back campaign. They can only rejoin by explicitly opting in again, for example, via a new signup or purchase checkout option. This ensures you communicate only with opted-in users.
Deliverability: Maximizes deliverability by eliminating non-responders, reducing spam complaints, and improving engagement metrics. This helps maintain a positive sender reputation with ISPs (like Yahoo Mail) and avoids being listed on a blocklist or blacklist.
Revenue Impact: Potentially sacrifices future revenue from genuinely re-interested customers who don't explicitly re-opt-in, but safeguards overall campaign ROI by focusing on an active list.
Compliance: Generally stronger compliance with privacy regulations (e.g., GDPR) by ensuring only actively consenting individuals receive marketing emails. Helps with managing unsubscribed users.
Suppression List
Process: Prevents marketing emails from being sent but retains the subscriber's data. Allows for potential re-engagement if specific non-email actions (e.g., purchase, transactional email interaction) are taken. This involves using a suppression list.
Deliverability: Can improve deliverability by not sending unwanted emails, but carries a risk if rekindled interest is misinterpreted, leading to sending to still unengaged contacts.
Revenue Impact: Provides an opportunity to capture revenue from passively re-engaged customers without requiring a new explicit opt-in for marketing emails.
Compliance: Requires careful consideration under privacy laws, as retaining data for potential future marketing based on implicit signals can be risky if explicit consent is not obtained at every re-engagement point.
Maintaining list hygiene and preventing unengagement
Ultimately, the best strategy is proactive prevention. Implementing robust email list hygiene practices from the start minimizes the number of unengaged subscribers you have to manage later. Here are some key best practices:
Double opt-in: Always use double opt-in for new subscribers. This verifies that the email address is valid and that the subscriber genuinely wants to receive your emails, setting a strong foundation for engagement and improving deliverability from day one.
Clear expectations: Clearly state what subscribers are signing up for, including frequency and content types. Transparency helps manage expectations and reduces future disengagement.
Segmentation: Segment your list based on engagement levels, interests, and purchase history. This allows you to send more relevant and personalized content, which is key to maintaining engagement. For example, you can segment your inactive subscribers before trying to win them back.
Regular list cleaning: Regularly review and clean your email list, removing hard bounces and addressing soft bounces promptly. This helps prevent your domain from being listed on a blocklist (or blacklist).
A proactive sunset policy is crucial. This policy outlines the actions you take when subscribers become unengaged, including when to trigger a re-engagement campaign and when to eventually opt them out or suppress them. It ensures that your emails reach engaged users and minimizes wasted resources on those who no longer find value in your communications.
Maintaining a healthy list is not just about avoiding penalties, but about building a stronger, more profitable email program. It ensures that your messages are consistently delivered and resonate with your audience.
Views from the trenches
Best practices
Implement a tiered re-engagement strategy, escalating from soft reminders to explicit opt-in requests.
Segment unengaged subscribers based on their activity patterns to tailor re-engagement messages.
Offer clear value propositions or incentives in re-engagement emails to entice interaction.
Define a strict sunset policy to automatically remove or suppress subscribers who do not respond.
Prioritize explicit re-opt-in for marketing emails after a period of inactivity, even for purchasing customers.
Not having a clear definition of an 'unengaged' subscriber, leading to inconsistent list management.
Delaying the removal or suppression of inactive users, which can negatively impact sender reputation.
Relying solely on re-engagement campaigns without a clear plan for non-responders.
Ignoring the pressure from internal teams to continue emailing inactive segments for perceived short-term gains.
Expert tips
Focus on domain reputation. If your deliverability and inbox placement are consistently good, your current strategy is likely effective.
The ideal re-engagement period (e.g., 6, 9, or 18 months) is not universal; it depends on your specific business and audience.
Consider a 'Goodbye' email in your re-engagement flow, making it easy for subscribers to confirm opt-out or reactivate.
For subscribers who opt-out but later engage (e.g., make a purchase), prompt them to re-subscribe during the checkout process.
A healthy email list is more about quality engagement than sheer subscriber count; a smaller, engaged list performs better.
Marketer view
A marketer from Email Geeks says they use a re-engagement campaign for users who haven't opened or clicked in 9 months. If no action is taken after three emails over a month, those customers are opted out, requiring them to re-opt-in themselves to receive emails again.
2019-09-17 - Email Geeks
Expert view
An expert from Email Geeks says that if someone shows interest, like opening those re-engagement emails, they might not need to be put back into the full-throttle loop of daily emails immediately.
2019-09-17 - Email Geeks
Prioritizing a healthy, engaged email list
The decision to opt out, suppress, or re-engage unengaged subscribers is a nuanced one that balances potential revenue with the imperative of maintaining excellent email deliverability. My experience shows that a proactive, data-driven approach is always best.
Start by clearly defining what 'unengaged' means for your audience and business model. Then, implement a thoughtful re-engagement campaign to give inactive subscribers a chance to reconnect. If they don't, leaning towards a full opt-out with a clear pathway to re-subscribe for truly interested individuals is often the safest bet for long-term email health. This approach protects your sender reputation, reduces spam complaints, and ensures your valuable emails reach those who truly want them.
Ultimately, a lean, engaged list will always be more effective than a bloated one that harms your sender reputation. Regularly auditing your list and adjusting your strategy based on performance metrics will help you achieve higher inbox placement and maximize the impact of your email marketing efforts.
Google and 
Yahoo, closely monitor how subscribers interact with your emails. Low engagement signals, like consistent non-opens or deletions without opening, suggest that your content isn't relevant to recipients. This can lead to a decline in your sender score, increasing the likelihood of your emails being flagged as spam for all recipients, even those who are engaged. It's a key reason why many email experts emphasize retaining an email list mostly comprised of recently engaged subscribers.
Yahoo Mail) and avoids being listed on a blocklist or blacklist.
