A bigger paycheck is far and away the biggest reason people take a new job. So if you want to keep your best people, make sure you're competitive. But the next three most common reasons center around the work environment--having interesting and fulfilling work, and good bosses. These factors haven't changed much over time. Back in 2004, when IT employment was again coming out of a recession, these factors also made up the top four, with higher pay no. 1.