URL plays a big role in SEO and duplicate post titles can negatively affect SEO performance of your website. If you are a WordPress admin then you must know that when you create a duplicate post titles then it adds a number at the end of URL slug. However, in SEO terms, it still counted as duplicate posts, and one should must avoid using of them.
How to Prevent Duplicate Post Titles in WordPress :
If you are using a blog with multi-admin then you will face duplicate posts frequently. To avoid duplicate post titles you can use Duplicate Title Validate plugin. When you create a new post and put title it informs you that “This title is unique”.
This, Duplicate Title Validate plugin does not only inform you about duplicate posts, when you will try to publish duplicate posts, it will stop you and post will be saved as draft showing a red notice, “Posted considered to have been released as a duplicate”.
The best part of this plugin is there is no configuration is required, just install this plugin and activate it, and now all done. Presently, Duplicate Title Validate plugin version 1.0 is available for download and compatible up to Wordpress 4.0.