When the platform changes its rules.
It isn't hypothetical. It happened to a client this year.
This spring, an email platform updated its acceptable use policy, and a client's whole product category landed on the wrong side of it. A few months later, a second platform sent the founder's account what read a lot like a warning.
So I asked the team one question. If the account closed tomorrow, what would you walk out with? The honest answer was a contact export, maybe. There'd be no automations, none of the emails inside them, no history, and no clean record of who had unsubscribed, which is the one thing a new platform needs before it can send a single email.
I built backups that run on their own. Every subscriber is copied off the platform every six hours, every automation and email is copied nightly, and an alert goes off if a backup ever stops. None of it has had to be used, and that's the point.
Roost is the same idea, built in from day one. Your list and everything you've built on it already live in your accounts.