if you're using a controller that NEEDS properties from a parent, use
nested routes. if you're using a controller that can assume the
parent, or it can be contrived, don't nest.
users controller, using devise for authentication, giving you the
private information singleton controller for data being stored only
for the current user, and not to be seen by other users
contact information controller, which stores personal contact
information, some of which can be seen by all users, depending on
resources :users do
that's how I approach it - however there is no right or wrong way to
do it. just remember routes provide information to a controller, and
aren't necessarily a representation of models (though that's a great
place to start).
hope that helps.