For newsletters this feature has been around for many years on my old @live.nl account from MS. have been looking for it ever since.
Would be nice if this 2015 idea would get implemented.

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 helpful

I wouldn't say for the folder but for filter, the auto delete after x hours feature can help a lot in deleting OTP or verification code email

Along these lines, how about an action in the sieve mail rules, that allow you not only to move or categorize, but also let set the maximum days to keep this mail in this rule?

I feel like this should be a basic feature at this point.

Yes please, why is this not implemented yet, like a "Rule" implemented in Outlook, for example. In fact, let's just have a comprehensive set of options to make into rules, similar to the way the "Filters" work so well at dealing with emails as they arrive.

Agreed that this is a needed feature. I would like to auto-delete my "Newsletters" folder after a month to clear it out. A bit concerning that this feature was first requested almost a decade ago and we still don't have it.

Aligns with this idea: https://protonmail.uservoice.com/forums/945460-general-ideas/suggestions/46541965-self-destruct-action-on-filters

https://protonmail.uservoice.com/forums/284483-proton-mail/suggestions/15831865-custom-expiration-after-date-trigger-for-receive

By folder or tag would suffice. Want options to auto-delete by calendar options (last day of the month; or, first day of the month, every Sunday at midnight, etc.)

Agreed, this is an absolutely critical feature. And I would also like to choose whether to include/exclude emails by tags, folders, contacts, starred etc to make sure only unimportant emails are deleted.

Would love to see this ability for folders, filters, etc. Use this with ZohoMail to get rid of frequent promotional emails. And yes, the ability also to choose the number of days after which to delete.

We need this asap.

This should be as simple as the implementation that, for instance, Fastmail has.

All folders can be set to "Delete messages after X amount of time", and there is simply a combobox or spinner to select the days/weeks, up to a year — or some other upper range.

Really need this asap.

Would love to set an auto delete option on emails in a specific folder

I fixed it for now by using IMAP from Thunderbird and adding a folder rule there.

yes, i would like e-mails from notifications@github.com to self-destruct after 1 day

This is an excellent idea, I get many notifications and after about an hour or 2 I don't need to see them. It would be nice to be able to set with the filter self destruct on messages.

i think, this can be achieved by setting this up for user made folders that can have a time sensitive auto delete contents feature, where the older contents inside can be set for a certain time that if they are beyond the allowed date will be auto moved into the trash. this way you can still have another 30days to retrieve them before they are gone permanently.

there is already a way of sorting the emails into folders, its just a matter now of putting custom expiry features for the folders, and of course certain folders can be assigned to never auto remove contents into the trash, by default.

i would use this for newsletters, where i could review the newsletters during the past yr or so, and the older ones will be auto removed into the trash.

Agreed, should be accessible/tie in via the label menu under actions (i.e. "Delete after X days") for things such as newsletters etc.