Use Path Redirect with PathAuto to Prevent Page Not Found Errors

If you've built your Drupal site, there's a good change you're already using the incredibly useful PathAuto module. If you aren't, then a simple summary is that PathAuto helps you better manage URL creation by assigning rules. This is an efficient alternative to manually choosing a URL for every piece of content, even if you use the simple default rule of having the URL created based on the Title of the content item.

But what happens when you decide to manually change the URL at a later time? Or perhaps your PathAuto rule uses taxonomy and you decide to re-categorize content. Depending on your settings, you could have PathAuto simply create the new URL and dump the old one. But this would lead to visitors getting a Page Not Found error since the former URL is no longer there. Or, you could tell PathAuto to leave the Old URL and create a new one. That helps prevent the Page Not Found issue, but now you have another URL for the same piece of content. This is generally considered to not be a "good thing" in regards to SEO.

Or you could simply eliminate these issues by using the Path Redirect module as well. This gives you another option in your PathAuto settings - now you can have the system update the URL in a visitor and search engine friendly way by automatically creating a 301 Redirect. This properly tells search engines that the content has moved, and it redirects visitors to the updated URL. It's a complete win-win!

A side note: If you aren't using the Global Redirect module as well, it would be a good idea. This will take care of the "system-specific" duplicate URLs.