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Email Deliverability Series Part 4: Maintaining a Healthy Email Marketing List

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May 17, 2024

By Alen Čapelja

Your email marketing list consists of all the subscribers you send marketing emails to. The contacts on this list and the way they’re organized can profoundly impact the success (or failure) of your email campaigns. 

Make sure you’re following these best practices to ensure your list is helping you reach the right people in the right ways so you can improve your sender reputation and drive engagement and sales.

What Is a Healthy Email Marketing List?

Let’s start with the end goal in mind. What exactly do I mean by “healthy email marketing list”? A healthy list is characterized by:

  • Clean data
  • Legal compliance
  • High deliverability
  • Personalization 
  • Engagement

In other words, it’s a list of contacts who are willingly receiving your emails and actively engaging with your content because it speaks to them.

Notice that the number of contacts doesn’t factor into our definition of a healthy email marketing list. Growing your email marketing list is a worthwhile undertaking, but only if the contacts you add are real and engaged. Put simply, we’re primarily going for quality over quantity. 

Best Practices to Jump-Start a Healthier Email Marketing List

So, how can you achieve the level of quality you’re after? Here are some best practices to put in place right now for a healthier email marketing list.

Opt-In Practices

The way you obtain contacts for your email marketing list can make a tremendous difference in the quality of your list. There are many ways you might collect email addresses, but the ideal approach is to have contacts voluntarily share their information with an understanding that they’ll receive marketing emails from you. 

Here are a few ways you can optimize your opt-in process:

  • Implement double opt-in: When a user signs up, send a confirmation email that requires them to verify their subscription. Double opt-in ensures that only interested and valid users join your list.
  • Be transparent: Clearly state what subscribers are signing up for and how often they'll receive emails. You can also allow subscribers to choose the types of content they want to receive in their inboxes. Transparency enhances trust and reduces unsubscribes and spam complaints.
  • Optimize sign-up forms: Place your sign-up forms prominently on your website and keep them simple. Although it is tempting to collect as much information as possible at the outset, you’ll encourage more people to sign up when you only ask for essential information such as the person’s name, email address, and demographic or psychographic information.

Note that you must also provide a clear and simple way for subscribers to opt out of future emails in order to remain legally compliant with relevant policies


When you try to write for everyone, too often, you end up writing for no one. You can deliver a more relevant and personalized experience by segmenting your email list based on factors such as user behavior, demographics, psychographics, and geographic information.

Start by collecting relevant data on your subscribers from sources including:

  • Sign-up forms 
  • Website behavior
  • Past email behavior 

Based on the collected data, categorize your subscribers into segments. When you create email campaigns, you should tailor the content for each of these groups. For example, the way you interact with a prospect who’s never made a purchase should differ from the way you interact with a loyal customer. Segmentation can help you turn disengaged contacts on your list into engaged ones.

Regular Cleaning

How many of your emails are actually making it into recipients’ inboxes? Whether emails are bouncing or landing in spam folders, a low deliverability rate is a sure sign it’s time to clean up your email list. Even if emails are delivered, if they’re guaranteed to be left unread by disengaged contacts, this can also negatively impact your email campaigns.

Periodically remove disengaged subscribers and incorrect email addresses to maintain your list health and deliverability. This involves:

  • Using email validation tools to check the validity of the email addresses on your list and removing nonexistent or incorrect email addresses
  • Regularly reviewing who is engaging with your emails so you can identify inactive subscribers who haven't engaged over a defined period, such as six months, and suppress them if you aren’t able to re-engage them
  • Running re-engagement campaigns to reactivate dormant subscribers where possible and keep your list active


If an email marketing list is full of unengaged subscribers, don’t start purging just yet. You may be able to turn it around and get these contacts to re-engage while creating a more engaging experience for future subscribers, as well. 

What makes an engaging email campaign is a topic too big to thoroughly cover here. We’ve already hit on some ways, such as segmentation and personalization. You can find some great resources online that cover a variety of other factors, from engaging email design to attention-getting subject lines. 

Although there are some best practices all brands can follow, there’s no one-size-fits all answer for engagement. Email marketers must find what engages their audience. And what engages one of your customer segments may differ from what engages another. Run with the data you have to design re-engagement campaigns tailored to each of your customer segments, and incorporate personalization wherever possible. Consider offering special deals, updates, or content that might spark a subscriber’s interest. Then, carefully track results and continue to refine your campaigns to turn inactive subscribers into active ones.

Monitoring and Improving Your Email Marketing List

There are steps you can take right now to clean up your email list, but achieving a healthy email list is really an ongoing task. Let’s look at a few of the ways you can continue to refine your email campaigns to maximize deliverability and engagement.

Track deliverability metrics.

Take advantage of tools and services to track deliverability metrics and identify issues. Email monitoring tools such as MXToolbox or your CMS platform can provide insights into your email deliverability, sender reputation, and more. Some metrics these tools can track include bounce rates, open rates, click rates, and spam compliance rates. Use the data to pinpoint areas for improvement so you can keep refining your list and your campaigns.

Use A/B testing.

Regularly test different aspects of your emails—including subject lines, calls to action, and sending times—by creating two versions and tracking the results of each. Be sure to only test one variable at a time and to send each version of the email to similar subscriber groups in order to get meaningful results. After the campaign, analyze the results to see which version performed better based on your predefined goals (e.g., higher open rates or click rates). Then you can apply the successful elements from your tests to future campaigns to continuously improve your email performance.

Set up feedback loops.

Determine which internet service providers (ISPs) your subscribers use most frequently, and set up feedback loops with those ISPs to receive notifications when recipients mark your emails as spam. This process typically involves providing information about your sending domains and IPs, and in some cases, you might need to authenticate your emails with SPF, DKIM, and DMARC

Beyond simply being notified of a spam complaint, you can set up a system to automatically process and act upon the feedback you receive. This usually involves removing complainers from your mailing list to maintain a healthy sender reputation. Regularly review the feedback to identify trends or common issues. High complaint rates from a specific campaign or content type, for instance, can provide valuable insights into what triggers negative reactions from your audience.


InLine CTA for blog content, Email Deliverability Series Part 1: The Fundamentals of Email Deliverability


Need to Refine Your Email Marketing List? Reach Out to Our Deliverability Experts!

The health of your email marketing list is key to your marketing success, so if you’re left wondering, “How healthy is my email marketing list?” or “Where do I even start?” it’s time to enlist some help. Our team is here to evaluate your list and help you work toward more successful email marketing campaigns. Let’s get started.


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Topics: Marketing Strategy, Email Marketing, E-Commerce Marketing