I completely agree with rgarrison. UTC isn't a refactoring opportunity, at least ideally. UTC is an up-front choice to make for a system - unless it's guaranteed to stay within a single time zone forever. Uh, yeah.... :-) Just moving my former sole proprietorship from Chicago to San Diego - without initially choosing UTC for mail, databases, logs etcetera - was enough to teach me that lesson; and working with business applications that span at least a couple (US) time zones (something to expect of "large" banks) has only reinforced it.