37. Product page must contain breadcrumbs (not applicable for one product stores)
Breadcrumbs are a secondary navigation aid that helps users and search engine robots easily understand the relation between their location on a page (like a product page) and higher-level pages (a category page, for instance).
Display breadcrumbs to make store browsing quicker for users. This way when a customer reaches a page they don’t want to be on, they can easily find their way back or go back a step or two and start over.
Additionally, this will help search engines recognize your website pages better – making finding your products online easier for potential customers.