How does content marketing outsourcing work if the content is on your area of expertise?

I assume we are talking about creating free content for customers or potential customers.

Unless you are understaffed or you need a specific type of content such as video or audio or other types that you do not have the expertise to create I would hesitate outsourcing.

If you do outsource the content, simply treat the outsourcer as internal staff that you manage on a daily basis until the content is complete.  That way the outsourcer can add scale.  If they bring a specific skill that you do not posess, you should ensure some transfer of knowledge from them to you takes. place.