Proper Klaviyo list hygiene for email deliverability means understanding why a smaller list actually makes more money. List hygiene is the email marketing practice that causes the most resistance. It feels counterintuitive: remove people from the list you spent money to build? But the math is clear, and the brands that resist list hygiene pay for that resistance in deliverability degradation and lost revenue.
The ghost subscriber problem
A ghost subscriber is someone who has been on your list for months and never opened a single email, or who was once active but stopped engaging 90 or more days ago. A ghost subscriber is someone who has been on your list for months and never opened a single email, or who was once engaged and has gone completely silent. They are not just failing to help your program — they are actively hurting it. Every email sent to someone who never opens generates a non-engagement signal. Inbox providers measure your engagement rate across your entire send volume. A large segment of non-openers pulls that rate down and signals that your emails are not wanted. This affects deliverability not just for the ghost subscribers but for your entire list. Every email you send to ghost subscribers signals to inbox providers that your emails are unwanted — degrading deliverability for your entire list, including people who love your emails.
When to suppress a subscriber
Standard threshold: any subscriber who has not opened any email in the last 90 days is a candidate for re-engagement. Standard threshold: any subscriber who has not opened any email in the last 90 days is a candidate for re-engagement or suppression. Before suppressing, run a two to three-email re-engagement sequence. If they do not engage with any of those emails, suppress them. After suppressing a large unengaged segment, programs consistently see: open rates increase by 10 to 20 percentage points, deliverability scores improve, and revenue per email increases because the remaining subscribers are the ones who actually open and click.
The Advanced Segmentation Strategy Guide covers the exact segments to build so you are sending to the right people from the start — $17 at signifystudio.com/library.
The re-engagement sequence that works
Email 1: The honest check-in
‘I noticed you have not opened any of our emails in a while.’ wanted to check in — is there something we could be doing differently that would make these emails worth your time?’ No promotion. No urgency. Just a genuine question.
Email 2: The explicit offer to leave
‘I have reached out and I do not want to keep showing up if you would rather not hear from us.’ If you would like to unsubscribe, here is the link. If you would like to stay, we would love to have you — just click here to confirm.’ The people who click to stay after being explicitly invited to leave are your most engaged subscribers going forward.
After these two emails, suppress anyone who did not engage. The list that remains is smaller and dramatically more valuable.
How often to do list hygiene
At minimum, quarterly. Run a report of subscribers who have not opened any email in the last 90 days. If that segment is more than 25 percent of your active list, run the re-engagement sequence immediately. Make list hygiene a calendar event — not a reaction to a crisis. The programs that stay healthy are the ones that clean regularly rather than waiting until deliverability has already suffered.
Need more tools and frameworks? Browse everything at signifystudio.com/library.
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