Every president gets sworn in once, but it's a smaller club of presidents who manage to get there twice. Here's a look at some recent presidents who served two terms. See who changed the most (or the least) in four years.
President Obama seems to have picked up a few gray hairs in the four years since he was sworn in on Jan. 20, 2009 (left). On the right, he's shown in December 2012.
Here's President Dwight Eisenhower and first lady Mamie on Inauguration Day in 1953 (left) and 1957 (right).
President Ronald Reagan posed for an official White House photo during his first year in office (1981, left). On right, he spoke to the nation early in his second term, in February 1986.
President Bill Clinton's January 1993 official White House photo (left) is stacked up against an image of him being sworn in for a second time on Jan. 20, 1997.
President George W. Bush greeted supporters at an inaugural ball in 2001 (left). Four years later, he was sworn in again on Jan. 20, 2005.
AFP/Getty Images /NPR
It's not just the presidents who can change a lot in four years. First daughters Sasha and Malia Obama were 7 and 10 on Election Day 2008 (left). Now, they are 11 and 14 (shown on Election Day 2012, right).