Definition
List hygiene: The ongoing practice of removing invalid, risky and unengaged addresses from a mailing list: verifying new signups, suppressing bounces and complaints, and sunsetting inactive subscribers.
What a list hygiene routine looks like
At capture: verify addresses on the form or through the API, and confirm signups with double opt-in where you can. After every send: suppress hard bounces, complaints and unsubscribes in every tool that sends mail.
On a schedule: re-verify segments you mail rarely and run a re-engagement series for people who have stopped opening or clicking. Before every import: verify the file and match it against your suppression list.
How often to clean an email list
It depends on how fast your list changes. B2B lists lose addresses every time someone changes jobs, so they need more frequent checks than consumer lists.
A practical rule: re-verify any segment before you send to it if you have not mailed it in a few months, and re-verify everything you plan to use for a big campaign.
What to remove and what to keep
Remove undeliverable addresses, disposable domains, hard bounces and complainers. Suppress them rather than deleting the records, so a re-import cannot bring them back.
Review the risky ones by type: catch-all addresses by their verdict, role addresses by campaign. Keep unknown results and re-check them later, since they are not a verdict on the address.
How RocketVerifier handles it
Bulk jobs take up to 100,000 addresses per file in CSV, TSV, TXT or XLSX, and a free list preview estimates the results before you are charged. Monitors re-verify a list of up to 5,000 addresses on a schedule, and 30+ integrations keep cleaning close to where your list lives. Duplicates and unknown results are never charged, and pay-as-you-go credits never expire.