Dead links are absolutely “no good” for your SEO, and even worse they are no good for your visitors!
There are two kinds of dead links. Links to external sites need to be monitored since the external site might change their structure, or they might even go out of business. In either case, new related articles need to be discovered, or simply kill the dead link.
Links to your own site sometimes go dead because of site structure changes. For example, if you’ve moved WordPress to a “different” subdirectory while migrating to a new hosting company, site destinations may have changed.
This article outlines a few free link checker sites that will review a site for dead links.
Add a header to begin generating the table of contents
dead link checker
On the first run, dead link checker actually discovered a dead link from the early days of google tag manager.
This was orphaned years ago. Unfortunately, it has stayed with the site through many development years. Turns out it is in the header.