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Hey Leigh! Can you clarify if the search engines are crawling the /category/article-title/ URLs or if your breadcrumbs just hint that it is the structure? Feel free to PM me the site if you want. Whether it's worth restructuring or not to add /category/ to the URLs depends on a lot of things. It's definitely helped on ecomm sites and I've recently done this with a marketplace I've worked with, which has really helped with rankings and longterm will really help with traffic. But you need to weigh it and the different considerations - all the redirects that need to take place, updating sitemaps, internal links, etc - against other things you could do to improve your rankings like building links and developing new content, as well as generally speeding up your site if needed. URL changes are never something to take lightly!