How long before ISPs deactivate idle inboxes?

ISP inbox deactivation timelines vary by provider:

Typical timelines:

6 months: Some providers send warning. 12 months: Account may be suspended. 24 months: Account likely deleted or recycled.

Provider variations:

Gmail: 2 years of inactivity before action. Yahoo: 12 months inactivity policy. Outlook.com: 2 years inactivity. Corporate accounts: Faster deactivation after departure.

What counts as activity:

Logging into webmail or app. Sending email. Some providers count receiving mail.

Implications for senders:

Sending does not prevent deactivation. Inactive subscribers become risky over time. Engagement tracking is essential.

Inbox deactivation timelines set the clock for address decay. Plan list hygiene accordingly.