List hygiene is the process of maintaining and updating your email list, making sure the contact information is up-to-date. An email list cleaning effectively removes duplicate contacts as well as removing inactive emails which can negative impact your email bounce rate and decrease your overall email deliverability.
Making sure your mailing list is up-to-date can be done through regular data cleansing. Doing this regularly will help keep it updated and relevant, by removing inactive, outdated or incorrect entries. It is best to do a proper maintenance of your data every six months to make sure the email addresses and contact information are reliable.