custom post type

It really depends on what you are building. I recommend not using extra plugins if your trying to build a high performance applications with lots of users and activity. However if you are building a small site with little traffic it does not matter really. You can use a plugin called p3 to check for plugin performance. You can take a look at the following if you are interested in coding your own custom post type.

http://codex.wordpress.org/Post_Types http://www.wpbeginner.com/wp-tutorials/how-to-create-custom-post-types-in-wordpress/

Personally I feel that good plugins don't cause that much of a performance failure. If you get a good plugin you should be fine and it's easier. My rule of thumb is use a plugin updated regularly that doesn't have a huge amount of extra fluff and you'll be fine.