A new survey from staffing firm Robert Half says 39 percent of American workers won’t use all their paid vacation time this year.

Saving the time for next year was the top reason for not using it, said 38 percent of survey responders. Another 30 percent said they’ve got too much work to do. Three percent say their manager frowns on employees taking vacation time.

Robert Half says there is more at risk by not taking a break from work than just burnout.

“It also erodes creativity, since stepping out of your routine frequently sparks innovation,” says Paul McDonald, senior executive director of Robert Half. “Fresh perspective is useful in just about any profession.”

McDonald suggests supervisors can lead by example by taking regular vacations.