It seems convenient to assign administrator privileges to a user especially if a user needs to change CRM settings frequently. However, for the daily work this is not recommended. Users with administrator privileges always see everything, inluding standard fields or picklist entries which has been disabled for the users. In addition, a user with admin privileges is not able to create the access for the outgoing Mail server.
If you want to switch between administrator an user interface quickly, use two different browsers instead. With one browser you login as admin, with the other as user.