Before you remove everyone who never opens

“Remove everyone who hasn't opened in a year” sounds like an easy maintenance rule. The trouble is that an open report isn't a reliable record of who read your email.

Tracking commonly relies on a small image loading. Images can be blocked. They can also load without the recipient reading the message. Apple's Mail Privacy Protection, for example, downloads remote content in the background.

That leaves you with possible errors in both directions: readers marked inactive and unread messages counted as opens.

Look at other evidence before removing someone. Replies, purchases, recent account use and explicit preference updates can tell you more. Clicks help, though security software can also follow links automatically.

The appropriate time window depends on what you send. A weekly newsletter and an annual renewal notice shouldn't use the same inactivity rule. A customer who ignores marketing may still need receipts and service messages.

Choose a policy you can explain: what activity counts, how long you wait, and which types of mail stop. Apply it consistently. Keep marketing subscription status separate from operational messages that remain necessary for the account.

When a subscriber leaves or a mailbox is confirmed nonexistent, honour that directly. You don't need an engagement score to overrule a clear unsubscribe or delivery failure.

Open rates can help you notice a change across comparable campaigns. They are a poor sole reason to erase an individual subscriber.