A short URL is often associated with good SEO practice. On top of that, a shorter URL is also easier to remember in case your visitors want to return to a blog post/page on your website via direct URL. While WordPress allows you to create a custom URL (be it for a new content or existing content), editing an existing URL is not good practice, unless you delete the old one after editing.
When you edit a certain URL of a blog post with a new URL, there will be two URLs leading to the same blog post. When visitors access your blog post via the old URL, they will be redirected to the new URL. If you often do this (editing the existing URLs), there will be too many URL redirects on your website, which will affect the page load speed. But no worries, you can delete the old, unused URLs on your WordPress site.
By the way, you might be confused between the term “URL” and “slug”.
URL (Uniform Resource Locators) is the entire string associated with a web page (e.g., https://utilizewp.com/best-wordpress-seo-plugins/). While slug is string right after the domain name (e.g., best-wordpress-seo-plugins).
Deleting Old Slugs in WordPress
In WordPress, slugs are stored in a table in database. You can find the slugs on the tmpfb4ceb_posts. That being said, you can delete the slugs via database. Alternatively, you can use a plugin if accessing database looks scary for you. In this post, we will show you how to delete the old slugs in WordPress using a plugin called Slugs Manager.
First and foremost, install the plugin and activate it right away once installed. Next, go to Tools -> Slugs Manager on your WordPress dashboard. On the Slugs Manager screen, you will be presented with the list of blog posts that have two slugs.
To delete the old slugs, simply select the old slugs you want to delete and click the Remove selected old slugs button. Or you can also click the Remove all old slugs button to remove all old slugs at once.