List hygiene is the process of cleaning your email address files to ensure the removal of all invalid, unsubscribed and inactive addresses as well as subscribers reporting your messages as spam (spam complaint).
Symptoms of poor list hygiene include having your IP addresses listed on blocklists, hitting spam traps or honeypots, high complaint rates and high unknown user rates. These metrics are known to directly impact your deliverability and mailbox providers use them to help determine your sender reputation.
As part of an overall list hygiene strategy, it is important to send only to the subscribers that are engaged and want to receive your email.
