Today’s CMS applications offer a huge variety of extension options, but this variety can be dangerous when it comes to security, so it’s very important to be selective when deciding which plugins to install.
Some tips: Check when the last update was done. Plugins that haven’t been updated for a year or more may no longer offer author support. Also, take note of the age of the extension and the number of installs. An established author is more trustworthy. Finally, make sure it comes from a legitimate source. Sites that offer free versions can sometimes be pirated and infect your site with malware.