Photo courtesy of Saundra Lohr
Courtesy of Michael McCaman
AscentXmedia/Getty Images
Kevin Dietsch/Getty Images
Jordan Siemens/Getty Images
FatCamera/Getty Images
Getty Images;Alyssa Powell/BI
A few years ago, Nathaniel Hudson-Hartman, 38, calculated that he'd need about $1.5 million in savings to retire comfortably in his sixties.