Email Configuration: IMAP or POP3?
Use POP if you...
...are the type of computer user who will only access your email using one email client (in this case Outlook). This way all your email is downloaded to you computer and you will always have access to your email whether you are online or offline. (If you use this setting, I recommend that have a robust backup system, since the only copy of your email will reside on your personal computer. You can configure Outlook to leave a copy of your email on the server, but you have a limited amount of storage on the server, so your email box could reach capacity and you will no longer receive email until you free up space.
Follow the instructions in the following link for steps to configure POP.
Use IMAP if you...
...access your email from multiple locations or devices and you are confident that you can configure your email settings properly. The IMAP email protocol enables a user to access their email from multiple interfaces while maintaining the presence and status of all the emails in your account (i.e. read vs un-read, replied/forwarded, deleted/moved/sorted, etc.). This is essential if you access your email from your computer in your office, your computer at home, your smartphone, a web browser on a shared computer, etc. The thing about IMAP is that you need to make sure it's configured to download the entire email message and attachments and you'll want to backup your emails to the local hard drive on one of your computers (gmail offers backup guarantees, but they are limited). I recommend IMAP to most computer users. It's especially helpful if you don't have access to your computer for some reason (because it crashed, or you forgot your power supply, or your dog ate it).
Follow the instructions in the following link for steps to configure IMAP.
Please remember that these are simply my personal preferences and recommendations, you are responsible for configuring, maintaining and backing up your own email. I cannot take responsibility for lost email or other problems that can result from improperly configured email clients.