Why bought lead lists decay, and what to do about it

A lead list is not an asset. It is a perishable good.

The decay rate is real

People change jobs, companies change domains, mailboxes get abandoned. A list that was 90% accurate when you bought it can be under 70% within a year — and you only find out through bounces, which also cost you reputation.

Verify before you send, not after

An SMTP probe checks whether a mailbox exists without sending a message: connect, ask the server, disconnect. Anything that fails goes out of the list. Catch-all domains (where the server accepts every address) get flagged rather than guessed at.

Re-check on a schedule

Verification is a snapshot. Re-run it every quarter on any list you are still mailing, and immediately after any campaign with an unusual bounce spike.

Keep researching instead of buying again

The sustainable version is a pipeline rather than a file: research new companies each month, verify as they enter, let an agent work the ones that have not replied, and drop the ones that have said no. That is exactly what AI Xiaoshizi is — LeadResearch plus an agent that follows up, on your own sending infrastructure.