Blog Upkeep

I have a question for all the other bloggers out there: Do you go back and fix old links? I have been keeping this blog for almost four years now. I know lots of old posts have broken links. Is it worth my time and energy to go back and fix them? I am not sure if this is worth my time or not. I want to know what the other bloggers out there do.

Please tell me what you do on your blog.