Creating a highly reusable Ecto API is one of the ways we can create long-term sustainable code for ourselves, while growing it with our application to allow for infinite combination possibilites and high code reusability. If we write our Ecto code correctly, we can not only have a very well defined split between query definition and combination/execution using our context but also have the ability to re-use the queries we design individually, together with others to create larger complex queries.

https://learn-elixir.dev/blogs/creating-reusable-ecto-code