What is list hygiene, and why does it decide whether you get delivered?

What it means

List hygiene is the habit of removing or silencing two kinds of contact: addresses that no longer work, and people who have stopped opening anything.

Those are exactly the two groups systeme.io names as the ones that limit deliverability. Addresses that are marked Bounced, and addresses that are inactive or unsubscribed.

Why it decides whether you get delivered

Email providers analyse campaign data and penalise a sender whose emails are not opened. Every inactive contact left on the list drags the open rate down, whether or not anything else is wrong.

Inside systeme.io that number is not cosmetic. Open rate is one of three metrics deciding which pool of sending IP addresses an account is placed in, alongside spam rate and bounce rate.

The reputation of those IP addresses is, in systeme.io's words, one of the most important factors in email deliverability, which is why the statistics decide the pool at all.

The number to aim at

systeme.io recommends keeping the open rate at a minimum of 20%, and reads the result like this: 20% and above is good, 10% to 20% is average, and below 10% means the list needs cleaning.

Cleaning by hand

The filters live in the CRM tab, under Contacts.

1. Turn on the Email activity filter and set a date in the field No email opened or clicked since. How far back you go depends on how often you send.
2. Add the Contact state filter and choose Has not made any payment yet, which leaves your customers out of the selection.
3. Select the result and delete it, or open More actions and choose Unsubscribe from all marketing emails.

systeme.io's worked example uses a one-month window: with today taken as 16 January 2026, the date entered in the field is 16 December 2025. What comes back is everyone who has not opened or clicked in that month and has never bought anything.

systeme.io recommends keeping customer data for accounting, so for anyone who has bought something, unsubscribing is the better of those two. It stops the emails without losing the purchase history.

The setting that does it every week

Hover over your profile picture, click Settings, then Emails, and scroll down to Automatic list cleaning. It offers two rows: one for contacts who have never purchased anything, one for contacts who have. Each row can either unsubscribe or delete.

The window is anything from 1 to 26 weeks without an open. Ticking a box means the clean runs every week from then on with nothing else to remember.

Each box is labelled as a full sentence. Set to 8 weeks, the four of them read like this.

systeme.io's recommendation for anyone keeping sales records for accounting is the unsubscribe version of each pair rather than the delete version.

Unsubscribing through this setting does not remove anybody from the contact list. It stops the sending and leaves the record in place.

How often to do it

systeme.io's advanced guidance is at least once a month. Its re-engagement guidance treats 3 to 12 months with no opens and no clicks as the usual mark of an inactive contact, depending on how often you normally send.

Try waking them before deleting them

A re-engagement campaign is worth one attempt before the list shrinks, and systeme.io sets out how to run one without hurting the account.

• Tag the inactive contacts and send to a slice first, 10% to 20% of the list, rather than the whole group at once.
• Follow up 3 to 7 days later with the ones who did not react.
• Treat anyone still silent after two emails as a contact to consider removing. Keeping them costs engagement rate.

Two limits on this. systeme.io advises against trying to re-engage contacts who have been inactive for a very long time, and it suggests deleting anyone past 12 months, or setting them to unsubscribed if the record has to stay.