We have been using the Wordfence plug-in for at least the last 8 years (perhaps longer). Can't say enough good things about it. It has stopped more attacks than I can count. Anytime I put up a new WordPress site, Wordfence is one of the first plug-ins I add before the site goes live. And yes, the premium version is worth it. I would also add that their technical support is equally awesome. I've only had to use it 2x in the past 8 years but in the most recent case, they promptly answered my support ticket and gave me the info I needed about their db structure that allowed us to create a bash script to extract the data we needed to help protect our network. A++++
