I'm reading applications .config file using .NET ConfigurationManager like it should be done, but .... Which one is most preferred option: Read config and store instance of (build in or custom) ConfigurationElement for later use Read config and store only needed values (but not instances of ConfigrationElement classes) for later use Read ConfigurationElement from config always when configuration values are needed These two things are in my mind: Performance impact in case 3 when reading config all the time Problems occuring in case 1 when using cached instances of ConfigurationElements