There are all sorts of arguments in favor of credit cards and against credit cards. No one can tell you exactly what the right choice is for your particular situation. However, if you decide to be a credit card user, make sure that you are a smart credit card user.
Fortunately, Ramit Sethi of I Will Teach You To Be Rich is offering free online access to the first chapter of his new book, (also titled I Will Teach You To Be Rich.) The first chapter is called Optimize Your Credit Cards. I love that Sethi stresses personal responsibility but gives you the information that you need to be responsible.
The book, which will be released next Monday (March 23, 2009) is a 6 week personal finance program for 20-35 year olds. It focuses on banking, saving, budgeting and investing; what Sethi calls "the four pillars of personal finance. Obviously, he doesn't address the unique situations of military members, but he provides an excellent education in general personal finance – something that will be useful now and still after you leave the service.