How to manage email storage on multiple MacBooks

What’s your goal here? Using either or both Macs as needed? Migrating from old to new? Using the old as a spare?

Trying to keep two Macs in sync is a little more complex and a little more involved, past Mail and past making sure to use IMAP and not POP (as is quite correctly mentioned above).

One option to sync contents uses Desktop and Documents into iCloud: Add your Desktop and Documents files to iCloud Drive - Apple Support

This sharing has some steps necessary to un-share, should you enable this feature. The steps are listed at the nottom of the linked article.

If you’re looking to migrate from old to new, that’s usually something the Apple setup or the Apple,migration tool deals with well.

You can connect your e-mail accounts to both computers. There Is no requirement to do so, but this may make life easier.

If you use Mail or another mail application, then e-mail will take up room on your drive whether you are using IMAP (recommended) or POP3. (With IMAP, the master copies of your e-mail remain on the server, which is much more convenient for synchronization between multiple devices. But each device may still cache copies of your e-mails.)

Using a Web browser interface to read e-mail does not require you to download all of your e-mails to your drive. It would be possible, to, say,

• Connect Gmail to Mail on one computer – so you could use Mail to read and send Google e-mail
• Use Safari and the Gmail Web interface on the other – to save some disk space at the cost of some convenience

No, it's not necessary to download emails to both your MacBooks. understand the given points here

Understanding Email Storage:

There are two main email account types:

• POP3: This downloads emails entirely to your computer. Having them on both MacBooks would duplicate storage usage.
• IMAP: This keeps emails on the mail server and only downloads the content (body and text) when you view them. Attachments are downloaded only if you choose to save them. This is the preferred option for multiple devices.

Check Your Email Account Type:

• Open Mail. app on your current MacBook.
• Go to Mail > Preferences.
• Select an account from the list.
• Look under "Account Information" for "Account Type."

Switch to IMAP if Needed:

• If it's POP3, contact your email provider (Gmail, Yahoo, etc.) and ask about switching to IMAP. They should be able to guide you through the process.

Manage Storage on Both MacBooks:

Reduce Existing Storage on Old MacBook (if POP3):

• • Delete old emails you don't need.
  • Use Mail's search function to find large messages with attachments and delete them (or move them to an online archive).
  • Empty your Trash folder.

IMAP Settings:

• • In Mail. app preferences, ensure "Store messages on the server" is checked for all accounts (assuming you switched to IMAP).
  • Consider enabling "Automatically delete messages from Trash after 30 days" or a similar timeframe.

I am sure after following these steps you can easily manage your account.

Thanx if you have any other query related to this feel free to ask!