The Spamhaus Project


What is an email sunset policy and why do you need one?

A sunset policy is an essential component of any successful email program. Find out why a sunset policy is essential and what you need to do to effectively implement one.

by The Spamhaus TeamNovember 29, 20234 minutes reading time

A sunset policy is a strategy deployed to rid your email database of old email addresses that are no longer engaging with your email. It is an essential tool for any email sender to maintain good email hygiene. With most modern mailbox providers effectively integrating sender engagement data into their IP and domain reputation algorithms, this has never been more important. Emailing old, unengaged addresses, you are at risk of significantly damaging your reputation.

Just as confirmed opt-in is the gold standard for email deliverability, saying goodbye to unengaged email addresses should be a vital part of your email playbook. Let’s delve into why a sunset policy is essential and what you need to do to put it into action.

Why do you need a Sunset Policy?

Unfortunately, most senders measure email program success by the size of their database. Except it’s the quality of the list that matters, not the size. You can find best practices and practical tips to achieve consistent email deliverability here – an email sunset policy is an extension of this guidance.

Without a sunset policy, email programs are vulnerable to four major pitfalls:

Increased exposure to spamtraps Recycled spamtraps are an effective way for mailbox providers and email filtering providers to evaluate sender’s list hygiene and use of best practices. For example, during the holiday season, well-known brands dig deep into their databases to boost sales. In doing so they are increasing the risk of sending to a larger number of abandoned mailboxes, leading to spamtraps hits and bounces. This is a strong indicator that subscribers’ signals should be paid more attention.

A rise in spam complaints As well as email frequency and cadence, incorrect audience targeting can cause spam complaints to increase.And the more unengaged your audience becomes, the more likely they are to mark your mail as spam.

Reputation deterioration Most email filters analyse the quality of the email stream they receive. A list with an increasingly unengaged audience indicates fewer people are interested in receiving the email and will be reflected in the reputation. This is crucial to note during a warmup campaign – particularly if you are sending from a new infrastructure – or if your reputation is already poor.Filters are trained to identify campaigns with a high volume of unengaged addresses and spamtrap hits before evaluating email placement. The higher the spam placement, the lower the ROI for the campaign. In other words, reputation will decrease where the number of old email addresses increases.

Informational listings A lack of sunset policy combined with poor bounce management is the recipe for inclusion on the Spamhaus Blocklist (SBL). As seen in our informational listings last year, ineffective bounce handling caused many users to send emails to addresses that had never engaged with their emails and had turned into spam traps. An effective sunset policy would have spared much pain for both the receivers and the senders.

How to effectively implement a sunset policy?

Implementing an effective sunset policy requires two important steps:

Email segmentation Email segmentation is crucial for any email program and plays a vital role in implementing a sunset policy. Segmenting by engagement is particularly helpful in optimizing email deliverability; pinpointing users who are no longer engaging with your emails.

In order to determine which addresses should be considered old, the sender’s email cadence and frequency of sending should be considered. And although spamtraps are aged (M3AAWG suggests 12 months as a minimum), it’s wise to use common sense when defining the age of email addresses in your database. Mailbox providers can investigate an email address that has been unengaged for anywhere from three to twelve months.

Engagement-based suppression The next step is to remove the email addresses from your lists that are no longer engaging with your emails – we call this  “adding to the suppression list”. If you’re worried about suppressing a large number of addresses, try re-engaging contacts with a permission pass or re-engagement campaign. This tactic does however come with a warning. A successful campaign requires strategic planning, as sending to all unengaged users at once is a sure-fire way to destroy your reputation!

As you would with a warmup campaign, schedule and stagger the re-engagement campaign over several days while paying close attention to domain and IP reputation. It is also good practice to contact mailbox providers and email filtering vendors to inform them of the possible inclusion of older addresses. As well as the proposed campaign timeframe. Once you have the final list of customers no longer interested in your mailing, it’s time to say goodbye!

For those who missed it, you can catch up on episode one of the Spamhaus Deliverability Live series, “What is a sunset policy and why do you need one?.