In my application I have a number of custom mixins that I apply to nodes in order to enforce certain schema requirements. Is it generally best practice to have a single application namespace for all of the application node types or to use separate namespaces for the different business objects being stored in the repository?
Honestly, I think this is entirely up to you. If you find you might have overlapping types with regards to names, I would go for different namespaces. Then again, you can always introduce a new namespace if you find you have conflicting names.