Capital Confusions

Welcome teammates! Let's begin the conversation by talking about capitalization and how we use it - or don't use it - in our daily business writing. I know that I, for one, have been totally confused by the use of capital letters in job titles. For example, it seems that the active duty personnel we work with like to capitalize words like Lieutenant or Commanding Officer when they are not used as part of a name, i.e. He had to visit the Commanding Officer before he left base that day. Shouldn't "Commanding Officer" be all lower case letters since it is a job title and not part of a name? What do you think? When should we capitalize job titles if at all? What are some of your "capital confusions" here at work?