Setting upload limits

You could check your threshold in a before_create callback.

E.g. with models User and Upload (this is untested, off the top of my head):

class Upload < ActiveRecord::Base
   belongs_to :user
   has_attachment etc.

   def before_create
     raise "Please no more - the horror!" unless user.uploads.count < 5
   end
end

Regards,
Andy Stewart