Ysterday my SIL bought an EFTA and the DOM was Jan 31, 2008 and the do not use date was Dec 31, 2013. We looked at another one in the store with a Dec 10, 2007 DOM and the do not use by date was Dec 31, 2013. Is this normal? I thought an 08 seat would go to 2014. We thought buying the "newer" seat would get more time. Or is is not worth worrying about?