I know I'm missing pages with my page level 301 re-directs. What can I do?

[VMLYRDiscoverability]

I am implementing page level re-directs for a large site but I know that I will inevitably miss some pages. Is there an additional safety net root level re-direct that I can use to catch these pages and send them to the homepage?

[JamesFx]

ErrorDocument 404 /

In the htaccess. Or spider the frick out of the site with Screaming Frog. There's an article on this;

http://www.seomoz.org/blog/8-ways-to-find-old-urls-after-a-failed-site-migration-whiteboard-friday

[VMLYRDiscoverability]

So there is not a way to put some kind of catch all re-direct without doing it at the root and redirecting everything to the homepage?

[Dr-Pete]

It really depends on the platform you're on and the way the page level redirects are set up, but if you list all the rules for the existing pages, you can always add a redirect at the very end. If implemented properly, anything left over should just that rule.

The alternative is to build a custom 404 handler that actually implements a 301-redirect to the new site.

I'd agree with this post, though - if the content really is dead, in some cases, it's better to let it 404 -

http://www.seroundtable.com/archives/022739.html

If you're really starting over, and for pages that aren't very active (no links, very little traffic), it can make more sense to clean things up. There's no one-sized-fits-all answer - it depends a lot on the scope of the site and the  nature of the change.