My passport is expiring in the next nine months so I plan to renew it soon to give the State department plenty of time to get it processed. They provide the option to get a drivers license-sized card for an extra $30 ($140 vs $110) - http://travel.state.gov/passport/fees/fees_837.html. Is it worth it? I have never seen one before except from sample pictures online. In the last 10 years, I have been to several foreign countries, but all of them would have required the full book even if I had the card. Thoughts?