I use MacOS Mail.app as my client and my mail backend is FastMail and I'm using IMAP. I am more than happy with the way these two work together. Just covering my bases, I'm wondering what my backup strategy is with this IMAP-based mailbox. If something happened at FastMail and my mailbox got nuked (not likely I know), what would my restoration plan be? I use Time Machine and I assume it's backing up my Mail.app data. In a disaster scenario, could I just restore my Time Machine data and have my mail in Mail.app such that I could export my various mailboxes and import them into another email system/provider/client?