If you want total protection I would advise to have all three shields running. They work as needed, for instance you move or open a file
then the file shield will scan that file. Or when you visit a website then the web shield will scan. The mail shield only works with certain
email clients. However if you use a web based email then the web shield will do the scanning. I only use web based email services, Yahoo,
Gmail and Outlook.com, but I keep the mail shield installed. So for me all the mail shield does is take up a tiny miniscule of HDD space and
let the web shield protect me. But if I decide to use Outlook or Thunderbird the mail shield is already up and running.