How to change URL the right way

Selected answers from the Dumb SEO Questions Facebook & G+ community.

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  Stockbridge Truslow: Unless all the pages there at the top level follow the same rule or there is some other clue in a consistent pattern (like do all courses have the word "training" in the URL and there are no pages that would be outside of the /courses/ folder that have the word training in them?) then you have to do them one-by-one.
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  Casey Markee: Are you on Wordpress running Yoast? Most likely, you STRIPPED the Categories from your URLs in Yoast because there is a toggle there that allows that. It`s located under the TAXONOMIES tab.
  
  Then, Yoast does the redirects automatically for you sitewide.
  
  Now that this is done I absolutely would NOT undo it. It will just take Google months to sort out your internal link architecture and there is little benefit to doing this other than creating further topical confusion.
  
  And yes, you will lose rank, temporarily, since Google has to recrawl and process all the URLS again.
  
  I`d convince your client it`s not worth undoing this. But if you DO then you have to find that setting, undo it, then do a sitewide redirect of the old URL catch-alls to the new ones.
  
  But minimizing internal redirects to prevent link equity dilution is always the way to go.