NEW YORK (CBSNewYork) — For many, just the thought of vacation is enough to make us smile.

Others will end the year with unused vacation days by choice.

As CBS2’s Dick Brennan reported, some find it hard to take time off and find it easier to be ‘overworked.’

“I find it difficult to be away for too long,” Andre Di Mino said.

Di Mino manufactures medical devices in New Jersey and said he loves his work and doesn’t miss taking vacation.

“Over the past many, many years I haven’t taken more than a week off at a time,” he said.

His employees also willingly forgo their own vacation days.

“Sometimes my husband does get annoyed with me, ‘oh you don’t want to take a day off,” Kayde Herrera said.

“I don’t want to fall behind, and just keep it going,” Tim Gilmartin said.

Gilmartin will pass up 15 vacation days this year, Kayde Herrara about 10.

They say they’re happy at work, and especially don’t want the backlog that builds when they’re away.

“I wasn’t here for a day, so now it is, what do I do first?” Herrera said.

Cait de Baun of Project Time Off said more than half of working Americans will leave unused vacation days at the end of the year.

“Fifty-four percent of us aren’t using that time off,” she said.

She said fear of leaving too much behind, of being replaced, or that no one else can do the job bare largely unfounded.

“Our research shows that work martyrs don’t get ahead. People who take vacations are more likely to get a raise or bonus,” she said.

Workplace expert Jeanne Meister agrees.

“I do not think they understand the health benefits of unplugging and taking time off to recharge yourself,” she said.

Some companies give cash incentives to take paid days off. One offers lump sum spending money.

“They get a bonus of a thousand dollars to take the vacation that’s due them,” Meister said.

Experts agree that managers need to lead by example when it comes to taking days off.

“If you have vacation time to take you should absolutely take it, and I tell my team that all the time,” Raquel Hudson said.

Hudson is a director at a digital video and media company, and may still end the year with about 15 days untapped.

“Now, I should practice what I preach, and that’s my goal to do that in the years to come,” she said.

Experts said unused vacation days could also be bad for the bottom line. There’s employee burnout from overwork, and if an employee leaves the company with unused days, they are entitled to be paid for them.