Shopify’s URL structure quirks
Shopify forces fixed path prefixes you cannot remove: /collections/, /products/, /pages/, /blogs/. That is fine in itself, but two things bite:
First, products are reachable at two URLs: the clean /products/item and a nested /collections/category/products/item. Left unchecked this creates duplicate content. Shopify usually canonicals the nested version to the clean one, but you should verify the canonical tag is actually firing on the nested paths, because themes and apps sometimes break it.
Second, deleted products return soft 404s or redirect to the homepage by default. Set proper 301 redirects to the most relevant collection or replacement product so you keep the link equity and do not frustrate users.