Wordfence is a very useful plugin for wordpress. However on most sites I have worked on recently, I have realized that most webadmins just install wordfence with default settings.
However if you are using Google Adwords, then do remember to uncheck the “Block access to the rest of the site (outside the login form)” in the “Country Blocking Options” within the “Blocking” submenu of Wordfence settings.
Wordfence also explain it here.
