Let's say I have a web site with a bunch of articles on it, with each article on its own page. Also, each page's URL has the title of the article in it, like this:
http://www.example.com/article/how-to-feed-a-walrus
If I create the article "How to Feed a Walrus", and a month later change the title to "How to Bathe a Walrus", should I change the URL to reflect this new title? The reason I ask is that if there are external links to the original URL, then those will no longer work since the URL changed. I don't want Google, for example, linking to a bunch of "Article Not Found" pages.