I've recently inherited a company site that's been around for a few years and has been through a few redesigns. In doing a website audit and also utilizing google's webmaster tools, I've found a ton of external links back to the site that are returning 404 errors.
My question is: Do I go through the list and manually setup redirects to the new location or do I leave them go to the 404 page?
It seems to me that I should set up redirects, but am wondering how this will affect SEO and search engine rankings. Is setting up redirects the best way to handle this?