The practice of removing unengaged, bounced, or invalid contacts from your email list to protect deliverability.
Definition
List hygiene is the ongoing process of pruning your email list. Hard bounces should be removed immediately (the address doesn't exist). Soft bounces should be tracked and removed after repeated failures. Unengaged contacts — those who haven't opened or clicked in 90, 180, or 365 days depending on your cadence — should be moved to a sunset flow that either re-engages them or unsubscribes them.
Without list hygiene, sender reputation degrades over time as engagement rates drop. Mailbox providers interpret a list with many unengaged recipients as a low-value sender and start filtering messages to spam.
How Wizel handles it
Wizel proposes a sunset flow as a default part of any new Klaviyo deployment. Lapsed contacts who don't re-engage after a final win-back attempt are automatically unsubscribed to protect deliverability.
Related terms
Email deliverability
Whether your email actually lands in the inbox vs the spam folder, promotions tab, or nowhere at all.
Sender reputation
A score (or set of scores) that mailbox providers assign to your sending domain and IP — drives whether your email reaches the inbox.
Win-back email
A re-engagement email or sequence sent to customers who haven't purchased in a defined period.
Last updated 2026-04-30
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