We recommend using IMAP as your email protocol where ever possible.
IMAP synchronises your email between your email program and the email server, this is especially useful if you have multiple devices accessing one email address, like a computer and mobile phone/tablet.
As an example, if you have a tablet and computer connecting to one email address.
Any emails you read on tablet will be marked as read on your computer.
This also works when deleting emails, any emails deleted on one device will automatically be deleted on any other devices connected to that email address.
The other major advantage of IMAP is should your computer or device suffer a major failure, your email will still be safely stored on the server and when you reconnect a new device they will all reappear.