Email list hygiene, explained

List hygiene is the ongoing practice of keeping your email database accurate, permissioned and engaged. It is maintenance, not a one-off cleanup — B2B lists decay roughly 2% per month as people change jobs.

The four hygiene layers

1. Capture Verify at the point of entry so bad data never lands in your database. A real-time check on your signup form blocks typos, [disposable emails](/disposable-email-domains) and non-existent mailboxes in under a second. Add a typo suggestion ("did you mean gmail.com?") to recover real signups.

2. Cleaning Re-verify any list older than 90 days, and always before a large campaign or an ESP migration. Remove invalids, segment [catch-all](/learn/catch-all-email) and [role-based email](/learn/role-based-email-addresses) addresses.

3. Engagement segmentation Split contacts by recency of engagement: 0–90 days (mail freely), 90–180 days (reduce frequency), 180+ days (re-engagement campaign, then sunset). Mailing the dead tail is what drags whole-domain reputation down.

4. Suppression discipline Maintain a permanent suppression list of hard bounces, unsubscribes and complainers, and apply it across every tool you send from — including your CRM and sales sequencer.

A maintenance calendar that works

• Continuous: verify at signup via the email verification api.
• Weekly: process bounces and complaints into suppression.
• Monthly: review bounce, complaint and engagement rates by segment.
• Quarterly: full re-verification of the active database with the bulk email checker.
• Twice a year: run a re-engagement campaign, then sunset non-responders.

What good looks like

• Hard bounce rate under 0.5%
• Complaint rate under 0.05%
• Unsubscribe rate under 0.3%
• At least 60% of the mailed list engaged in the last 180 days

Smaller and cleaner beats bigger and noisier. Cutting a list by 30% frequently raises total clicks because more of the remaining mail reaches the inbox.

Compare your numbers with the deliverability benchmarks.