The only sort of chronological measurement with any sort of meaning whatsoever is relative, but it seems life is based around a series of arbitrary and restrictive blocks of time into which things absolutely must be divided. Because the days December 31, 2009 and January 1, 2010 are in two totally and irreconcilably different eras; therefore, everything about the world and its technology, fashion, sociopolitical structure, geography, economic condition and climate will change right there on the dot at 11:59:59.99 (as opposed to gradually over months and years and decades).
Although people love poorly-designed resolutions and sickeningly premature nostalgia and naive hope on the last day of the last month, the truth is that no day of the year is any more significant than any other. December 25th comes once every year. August 13th comes once every year. Your birthday comes once every year, as does the anniversary of the first time I held a welding torch. Things rust, things grow, things are born, and things die on their own timetables. It simply does not matter what day we decide to brazenly declare "ALL RIGHT UNIVERSE IT'S ABOUT TIME SOME SHIT BECOMES DIFFERENT FROM THE WAY IT WAS WHEN I STARTED THIS SENTENCE".
I am not watching the ball drop, I am not singing Auld Lang Syne, I am not drinking champagne. I am going to put the beginnings and ends of my own life's stories wherever (and whenever) the hell I want.