Your list decays over time: people change addresses, work inboxes get shut down. On average, 20-30% of addresses go bad every year.
What a clean list buys you
- Lower cost: you're not paying to email addresses that no longer exist.
- Stronger reputation: a low bounce rate signals trustworthiness to mailbox providers.
- Honest metrics: your open rate reflects the audience you actually have.
A simple routine
Run a full verification before every major campaign and once a quarter. Credits never expire, so they're there whenever you need them.