Should you use POP3 or IMAP?
The first thing you need to do before making a decision is to understand what POP3 and IMAP are and the difference between the two.
What they are
Both POP3 and IMAP are mail protocols that email services use to receive email, be it to an email client such as Outlook or a mobile device.
POP3 – Post Office Protocol 3 is a protocol that has been around for decades. It’s the standard way that a mail service will receive email from a mail server.
IMAP – Internet Message Access Protocol is a protocol that is much newer then POP3 and is used by mail products to view your mail as opposed to actually downloading it.
What is the difference to me?
If you decide to configure your email client or mobile device to connect to your mailbox using POP3 then what happens is that the client or device contacts the mailbox and allows them to download the contents of the Inbox to their own local storage. The mail then will only exist on that local storage and would not be available to download via another client or device. It is however worth noting at this point that a number of clients and devices do allow you to enable a setting to ‘keep a copy of the email on the server’ this would then allow them to be download via a second client if required.
When using IMAP with a client or device they will simply connect to the mailbox and display the full mailbox to you without actually downloading the content to local storage. This has the benefit of allowing you to manage your mailbox from multiple clients and devices and seeing the same content.
If you think about your mailbox as a post-box full of letters, and your mail clients and devices as postmen it can become a little easier to understand the basic fundamental differences between the two protocols.
When using POP3 a postman would visit the post-box and empty the contents and take it away with him. If a second postman then arrived he would only have access to the letters that had been placed into the post-box since the first visit.
When using IMAP a postman would visit the post-box and take a copy of the letters and take those copies away with him, then when a second postman arrived he would do the same and still be able to see all of the letters placed into the post-box.
Which one should I use?
Which protocol you decide to use depends mainly on how you will be accessing and managing your email. If you are likely to be viewing your mail from multiple locations, clients or devices then It is usually best to use IMAP. IMAP will allow you to manage your mailbox from all of these different locations and clients while the actual mailbox content remains on the provider’s mail server. If you were to do the same using POP3 with the ‘Keep a copy on the server’ setting enabled then you are in essence simply creating multiple copies of your mailbox and any management of the mail into sub folders would need to be repeated on each individual client.
If you are simply going to be using one email client and do not want to worry about reaching the mailbox size limit, due to the amount of email, then POP3 would be the way to go. This provides a simple service to allow you to download all of your mail to one location managed by you. The mailbox on the provider’s server would always be empty or close to it as a result and so you would never need to worry about reaching the limit.
If in doubt use IMAP, this gives you the ability to manage your mail from a client or device while still giving the peace of mind that there is a backup, on the mail provider’s server, of your mail. However if you are only accessing your mail from one place and need to keep all your mail locally, POP3 may be a better option.