A bigger email list is not a better email list. The subscribers who never open are actively hurting the ones who do.

Here is what nobody tells you about email list size. That 100,000-subscriber list you are proud of? If 40% have not opened an email in 6 months, they are not just dead weight — they are actively damaging your email program. Gmail, Yahoo, and Outlook watch your engagement metrics. When a large percentage of your emails go unopened, inbox providers conclude your emails are not wanted. So they move more of your emails to spam. Including the emails going to your engaged subscribers.

Your deliverability drops. Open rates decline. Revenue per send shrinks. And the irony is crushing — the subscribers you want to reach are seeing fewer emails because the subscribers who do not care are dragging your sender reputation down.

A sunset flow fixes this systematically. It identifies subscribers who have stopped engaging, gives them one final chance to re-engage, and then suppresses those who do not respond. Your list gets smaller. But it gets radically more effective. Open rates climb. Click rates improve. Revenue per send increases. And inbox providers start trusting your emails again because your engagement signals improve.

We build sunset flows in Klaviyo for eCommerce brands. The result is always the same — smaller list, more revenue, better deliverability.