I’m in the process of reviewing several wordpress membership and shopping cart plugins and there have been some very obvious points that I think are worth discussing when you are in the process of purchasing one of these plugins.
1. When was it last updated?
Because WordPress is so popular it is also a target for hackers. We’ve seen a few major breaches over the years (such as the timthumb.php exploit) and one of the most important ways to minimise your exposure to possible breaches of site security is to make sure you have the latest version of WordPress as well as the latest version of any plugins or theme you are using. If a plugin hasn’t been updated for a year or more then that tends to ring the alarm bells for me. Either the author is so confident that they don’t believe their plugin is vulnerable or they are displaying apathy and will continue to do so until a major breach occurs.