Assuming you are using only the webmail interface and your browser, the only two folders with deletion schedules are the Spam and Trash. In all other folders emails should remain indefinitely until you delete them. The older Zimbra email format had deeltion schedules you could change, but the newer Appsuite does not. If you are using a desktop email client or a mail app, those might have adjustable schedules.
Thanks for clearing that up. I've been relying on that old feature that is not available so my box just keeps growing. If Comcast is listening, please note that scheduled email deletion is very important especially to those of us who get a few hundred emails a week.
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