README.md in nested_set-1.6.3 vs README.md in nested_set-1.6.4

@@ -34,9 +34,11 @@
       def self.down
         drop_table :categories
       end
     end
 
+###NB: There is no reason to use depth column. It's only add additional queries to DB without benefit. If you need level you should use `each_with_level` instead.
+
 Enable the nested set functionality by declaring acts_as_nested_set on your model
 
     class Category < ActiveRecord::Base
       acts_as_nested_set
     end