Links break for lots of different reasons. Websites can disappear altogether or they can be reorganized. Even if you don't have many links to other websites, making changes to your own site can break links.
How do you handle broken links? Do you check your sites regularly for issues, and if so, how do you do it? Do you use tools like Xenu or Screaming Frog to find bad internal and external links on your sites? Do you review crawl errors reported by Google Search Console? And when you do check for broken links, do you find it is a worthwhile effort in that you find changes you should make or not?
Michael