If you have ever changed a URL on your website, or your permalink structure without adding redirects you could have a serious problem on your hands.
But why is this a problem?
Changing URL’s without adding redirects causes problems with search engines like Google, it stops them from indexing your content and can impact your rankings.
It’s also a huge problem for users – if they find a broken link then that’s a lost opportunity for you and it’s frustrating for them, they may never return.