Why your email program needs a sunset policy and how to implement one

Email programs thrive on engagement. But what happens when subscribers stop opening, clicking, or caring? Continuing to send to unengaged contacts doesn’t just hurt your deliverability, it also wastes budget and skews your performance metrics. That’s where a sunset policy comes in. It’s your safeguard against poor sender reputation, inflated lists, and declining engagement.

In this post, we’ll walk through why every brand needs a sunset policy, what makes an effective one, and how to implement it without losing valuable subscribers.

What is a sunset policy?

A sunset policy is a set of rules for when and how to stop emailing inactive subscribers. Think of it as spring cleaning for your database. The goal isn’t to delete people recklessly, it’s to maintain a healthy list, improve deliverability, and ensure your emails reach people who actually want them.

Most marketers define inactivity by a period of non-engagement, such as no opens or clicks for 90, 120, or 180 days. The right threshold depends on your sending frequency, audience behavior, and product.

Why you need a sunset policy

1. Protect your deliverability

Mailbox providers like Gmail and Yahoo track engagement signals to decide whether your emails belong in the inbox or the spam folder. Sending repeatedly to inactive users tells these providers that your emails aren’t wanted, as poor list hygiene is one of the top three causes of deliverability issues. .

2. Improve data quality

Inactive subscribers are dead weight that artificially deflate your overall engagement metrics. They make it harder to measure the true impact of your campaigns and identify successful content.

By segmenting or removing these contacts, you gain a clearer, more accurate view of what’s genuinely working. For example, your blended open rate across your entire list might be 15%, but removing the inactive segment might reveal that your engaged audience actually has a 35% open rate. A clean list means better data, leading to a stronger strategy.

3. Save on costs

Most ESPs charge based on contact volume. Cleaning your list means you’re only paying for people who actively engage, improving ROI over time.

4. Respect your subscribers

A sunset policy doesn't just passively clean your list; it actively prompts your least engaged subscribers to make a decision. By reaching out with a targeted re-engagement campaign, you are giving them a compelling choice: to reaffirm their interest or to quietly unsubscribe.

This approach shows respect for your audience’s inbox, minimizing the frustration that leads to spam complaints. Ultimately, this transparency strengthens your brand perception and trust, leading to a smaller, more committed audience that is more likely to engage and convert after the process is complete.

How to build and implement your sunset policy

Step 1: Define “inactive”

Start by setting your inactivity criteria. This definition is not one-size-fits-all and should reflect your business model and, crucially, the typical sales or repurchase cycle of your product. Open and click data are the obvious place to start, but to build a truly complete and effective sunset policy, you must look beyond the email client. Your definition of activity should ideally include:

• Site Activity: Has the user logged into their account, browsed a product page, or added an item to a cart? A user who hasn't opened an email but visited your site last week is an active prospect.

• Purchases: Has the user made a recent purchase? An apparel brand might want to stop promotional emails to a non-opener, but a mattress company or appliance store should classify a user as "active" for a much longer period after a purchase, perhaps only sun-setting them years later when they are due for a replacement.

• Mobile App Usage: For a mobile app or gaming company, the most important metric is often the last time the user launched the app.

Here are some examples on how to integrate customers’ activity with your business’ sales cycle:

Short Purchase Cycles (High-Frequency Engagement)

These businesses rely on frequent communication and have a quick turnaround from prospect to customer. The definition of inactivity must be narrow to maintain high list hygiene.

Medium/Long Purchase Cycles (Account-Based Engagement)

These businesses deal with professional clients, have complex buying processes, or offer products with an expected life span that is several months long. The inactive window must be longer to respect the sales journey.

Very Long or Infrequent Purchase Cycles (Relationship-Based)

For products that are purchased rarely (e.g., once every 5+ years), the standard open/click metric on a promotional email is nearly useless. The definition must shift to incorporate site and purchase history.

Step 2: Create a re-engagement campaign

Before removing subscribers, give them one last chance. A re-engagement campaign can remind people why they signed up and offer them value to stay subscribed. Try:

• Highlighting benefits they may have missed

• Offering a small incentive or exclusive content

• Asking them to update preferences (e.g., email frequency or topics)

For creative examples, see Scalero’s email re-engagement campaign guide.

Step 3: Segment and pause unresponsive users

After your re-engagement effort, move anyone who doesn’t respond into a suppression segment. Don’t delete them right away, instead pause sending for a defined period (such as 30–60 days) before full removal.

Step 4: Automate the process

Build automation in your ESP (like Klaviyo, Braze, or Customer.io) to manage this process continuously. Include triggers for:

• Continuous Identification: Automatically flag and segment users as "inactive" the moment they cross the defined time threshold (e.g., 90 days of no engagement).

• Triggered Re-engagement: Initiate and send the multi-step re-engagement campaign series exclusively to the newly flagged inactive segment.

• Automated Suppression: After the re-engagement series is complete, automatically move any users who failed to engage into a suppression segment. This immediately removes them from your active billing count, thus reducing your paid contact volume and saving costs on your ESP subscription in the long run.

Step 5: Monitor and adjust

Track metrics like open rates, spam complaints, and list growth rate before and after implementing your policy. Always be prepared to adjust your inactivity thresholds based on performance. For instance, if your spam complaints suddenly drop, you know your criteria are working. If your list growth rate stalls but your revenue-per-email rises, the trade-off is likely worth it.

For a deeper dive into deliverability best practices and tracking, you may find additional helpful resources on our Intro to email deliverability page.