There are a few ways that webmasters goes about avoiding broken links to and from their website. You can choose to do either or both as it can make managing your server and website less of a hassle.
Incoming Broken Links
To correct incoming broken links, you can create a redirect in the .htaccess file. I had to do this years ago because a link to the site got translated to Spanish and was trigguring the 404 page and user would skip my page in the search results as they assumed it would be the same as well.
RedirectMatch 301 ^/casa\.php$ /home.php
Outgoing Broken Links
Linking to external content is simple as printing the source’s page to a .PDF file using CutePDF then uploading the file to dedicated folder on your server. Once that task is complete, embed a link to the .PDF file from your article. Now, your visitors will get the info they need and remain on your website where they may bookmark your page (and not the source) or check out other pages.