Why use IMAP vs POP email
If you ever loose emails its a very frustrating thing. Getting them back can be tricky at times. My view is if you use many devices like laptops and smart phones and tablets IMAP is better as it keeps a copy on the server. If you delete an email it deletes it from the email server.
POP gets the email from the server and when you read it it comes off the server and downloads to your device. If you ever loose your laptop or change email clients or do something wrong within your email client all emails are gone. If you must use POP email then please back up your emails.
If your using a MAC I would recommend using Time Machine that comes with Apple Macs and backup your emails and files to an external hard drive.
Below is a visual of both POP and IMAP email