As noted in Finished Moving: Lessons Learned link rot is real.
Links vanish.
I've got 23 ancient (2004 to 2006, ancient) posts with clearly broken links. These are easy to identify because the service vanished years ago.
The tricky part is figuring out of there's any content worth preserving. In many cases, the blog post was really an extended response to someone's forum question.
If I can recall the back-story, the blog post may be of some interest. If I can't recall the context, then, I'll need to delete it.
First, however, I've got a book outline and schedule to finish.