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Sean It's not really necessary to use canonical url's. If you are sure that every piece of content on your site is available on a unique url you don't need to implement them. It doesn't hurt having them either. Using canonical url's (if implemented properly) can help to avoid duplicate content issues. Like Patrick mentioned, having canonicals doesn't imply that no duplicate content issues exist (I've seen sites where the canonical url is always equal to the url - which renders them completely useless) Crawl tools like Screaming Frog are the best option to check if you need canonicals, and if you have them, to check if they are properly implemented. rgds, Dirk