g1smd - 6:39 am on Sep 30, 2011 (gmt 0)
That's an important point. Make sure that there are no broken links within the site.
The only issue will be where people click on an out of date link in the SERPs, or from another site, or in their bookmarks. That's why the suggestion is to redirect URLs that have traffic and a useful equivalent page of content, and 410 those that do not.
Run a Xenu LinkSleuth report before you start work. Save the data so you can refer back to it again and again.