A broken link is where the link leads to a 404 page (a page not found).
Broken links on a website can be very frustrating for the end user. They also reflect badly on the site, as it looks tardy. Internal broken links are inexcusable, whereas external broken links are sometimes out of your control.
All links should be checked periodically, and any broken links fixed or amended. Broken links have an adverse effect on your analytics as they will increase your bounce rates and will reduce your time on page metrics.
Every time you make a structural change to your website you should check your links and if they are faulty you should make some redirects.
Google have said that broken link don’t directly affect your SEO, but the SEO metric is made-up of many items including user experience and your bounce rate, which broken links will have a direct effect upon.
You can test your own site very quickly via www.brokenlinkcheck.com. The best way to deal with dead links is to add a plugin to WordPress which will perform a scan, say once a week, and will then email you with the results.
Broken Links - What we can do
Initially scan the site for broken links
Update, fix or amend the faulty links
Once repaired, put in a facility to constantly monitor ‘link health’ and instantly report any broken link. These will be fixed.