The decision that matters most.
WHAT IMAP DOES
Keeps mail on the server.
Every device sees the same mailbox, with the same folders and the same read status.
Deleting on one device deletes everywhere.
WHAT POP DOES
Downloads mail to one device, usually removing it from the server.
Other devices do not see it.
WHICH TO USE
IMAP, for almost everyone.
WHEN POP MIGHT SUIT
One device only, and you want mail off the server.
Rare now.
WHY POP CAUSES PROBLEMS
Mail downloaded to one device and gone from everywhere else.
Frequently the cause of "my email disappeared".
THE STORAGE CONSIDERATION
IMAP keeps everything on the server, consuming your quota.
Manage it: archive, delete, and empty Trash.
WHAT TO CHECK
Which your devices are currently using.
Mixed settings across devices cause the most confusing problems.
WHAT TO DO ABOUT MIXED SETUPS
Move everything to IMAP, carefully, after backing up.
