Up until recently, WordPress gave two options: You could either disable comments and trackbacks by default for all pages and posts, or you could have them active by default. In WordPress version 4.3, this finally changed so comments are always disabled on new pages.

While the new change makes it easier for many of the sites, it make it harder for people who need to get the reverse and enable comments on all pages, or if they need to change the default for a custom post type. This plugin allows you to choose whether comments are enabled or disabled by default on all new posts, pages and custom post types, while still giving the ability to individually enable comments on posts or pages.