How long do email messages stay in trash folder?

You can select how long messages will stay in trash before they are permanently deleted.

Open your apple mail app by clicking on the postage stamp in your dock, then click the word Mail in the upper left corner of the computer screen.

Next, choose Preferences, select Accounts from the top of the preferences screen.

Then, select the mail account name from the left sidebar.

Next, Click the Mailbox Behavior tab, go down to trash options and click the drop down under "Permanently erase deleted messages when:" and choose the timeframe that works best for you.

Example of the section you are looking for if you're running Mac OS X 10.10:

Hope this helps.

Use the Settings app to select how long items remain in the trash in iOS.

Settings > Mail, Contacts, Calendars > Your Mail Account > Advanced (scroll down) > Deleted Messages > Remove

The choices are: Never, After One Day, After One Week, and After One Month

You can also delete them immediately in the Mail app.

Mail > Your Account > Trash > Edit > Mark those you want to delete, or tap Delete All

You're welcome!