This would be a helpful feature. But from a UX perspective, I would make it configurable on a per address basis.
I would suggest this flow:
1. Allow users to set the max. lifetime of messages in the Trash folder (from 0, disable trash functionality completely to 30 days)
2. Allow users to set the max. lifetime of email messages, i.e. the "auto delete" functionality
3. Show a new tab "Expiring Soon" on the left side, just like for scheduled messages, when the functionality is activated.
4. Move email messages to Trash.
This allows fine-grained control over both expiring messages and a "grace period" for messages that have been moved into Trash.
This would be a helpful feature. But from a UX perspective, I would make it configurable on a per address basis.
I would suggest this flow:
1. Allow users to set the max. lifetime of messages in the Trash folder (from 0, disable trash functionality completely to 30 days)
2. Allow users to set the max. lifetime of email messages, i.e. the "auto delete" functionality
3. Show a new tab "Expiring Soon" on the left side, just like for scheduled messages, when the functionality is activated.
4. Move email messages to Trash.
This allows fine-grained control over both expiring messages and a "grace period" for messages that have been moved into Trash.