I was checking my Google Webmaster Tools and found a few errors with my links. I have gone through opening and closing sites. The number of sites are more than a dozen.
However, with this site, I found 9 errors within my site dealing with dead links. So, if you have not used the Google Webmaster, Tools, perhaps you should really consider it. You can learn a lot. Dead links are important to take care of and depending if you blog quite a bit, this will save you the time. The tool tells you where the dead links were found.
Now, it is a no brainer that most know dead links should be removed, but how many really go through older posts to look for old sites that are dead? Even further, do you look for internal pages that you linked that you have either removed or in the case of WordPress, changed the permalink structure? Most of the time external dead links are removed while the internal ones collect dust. Even if you did not have much faith in Page Rank, this is definitely another reason why you should use Google Webmaster Tools.