What is a sunset policy?

Pick a window that matches your sending frequency. A weekly newsletter can sunset at six months; a quarterly product update needs eighteen, because a recipient has had fewer chances to engage.

Define engagement before you define the window. Opens are increasingly unreliable thanks to privacy proxies loading images automatically, so clicks, replies and purchases carry the real signal.

This is the rule that removes recycled spam traps, and it does so without needing to identify one. An address that stopped engaging two years ago is exactly the profile a provider recycles.

Run the re-engagement sequence first, then remove. The sequence is the courtesy; the removal is the policy, and it should happen on schedule whether or not anyone reviews it.

Here's a rule for a weekly newsletter, in terms a platform can execute. Entry condition: subscribed for at least 90 days and received at least 26 sends, with no click, reply, purchase or login in that time. Action: move to a re-engagement sequence of three messages over 14 days. Exit: anyone who clicks returns to the main list with their counter reset, and everyone else is suppressed on day 15.

Say the list is 80,000 and the first run flags 19,000. That first batch is the backlog, and it's far larger than what the rule will catch once it's running nightly, when you'd expect a few hundred a week.

Two exclusions belong in the rule from the start. New subscribers need the 90-day grace period, or you'll retire people who joined last month and simply haven't clicked yet. Recent customers should be exempt on a purchase date, since someone who bought in the last six months is engaged with you even if they ignore the newsletter.

Sunsetting should move people to a suppressed state and leave the record in place. Deleting loses the consent history you may need later. It also lets the same address come back through an old import as though it were new. A suppressed record blocks that, and it means a person who signs up again through your form can be reactivated cleanly, with a fresh consent date.

The rule covers marketing mail only. Receipts, password resets and account notices go to everyone who needs them regardless of how long they've ignored your newsletter.

Consider a step before the exit. Someone who's stopped clicking a weekly email may be perfectly happy with a monthly one. Try dropping quiet subscribers to a monthly digest after three months. Sunsetting only those who ignore that as well keeps more real readers than a single cliff.