A common question we get when people are setting up their email client is "should I use POP or IMAP". The answer depends on how you plan to use your mail.
We'll start by describing the differences between the two protocols.
POP was designed when people had just one device to read mail with, usually a desktop computer. The usual mode of operation is that your device connects with the mail server, downloads any new mail, removes it from the server, and then disconnects.
IMAP is a more recent protocol designed to support multiple devices. Mail is retained on the server until it's deleted, allowing multiple devices to synchronize. When a message is read on your mobile phone, it's marked as read on your desktop, in webmail, etc.
IMAP sounds like a no-brainer, right? Not so fast. The problem with IMAP is that any message that's not deleted stays on the server forever. Usually it's not too long before you're dealing with full mailbox warnings, and in the worst case incoming mail might get bounced if your mailbox is full. The only way to resolve this is to archive older messages to your laptop or desktop. Unfortunately, each email client tends to have a different way of doing this so it's not easy to provide clear instructions on how to create an archive.
So what's the best approach?
If you're just running one device, use POP.
If you use multiple devices and you're an "Inbox zero" type, deleting every message after it's been dealt with, use IMAP.
If you use multiple devices and are an email hoarder, keeping everything, then it's possible to set up POP in a way that might work. One option in POP is how many days to keep read mail on the server. This defaults to zero, but it can be useful to set it to a larger value, for example 14 days. Then you can set all your devices to use POP. You lose the synchronization of "message read" states, but you know you can access the last 14 days of email on your mobile, while still being confident that your desktop has a copy of all your messages.
