The Yahoo Mail is now much bigger. Nowadays you have a maximum of 1 TB of space. If you do notice that it is filling up, then it is smart to clean the mailbox. You can do that in different ways. This way you can back up your emails. Empty your trash. Delete old mails and folders. Also check for emails with large attachments. It is important to pay close attention. Do you use IMAP? Then you will lose everything you delete for good, it is no longer on the server.