NEW YORK — When Justin Stewart started his career, he juggled several jobs to make ends meet. He poured himself into his full-time role as a news show production assistant from 3 a.m. until noon. Then he rushed to the airport where he rented cars or to the big box stores where he pulled retail shifts.

Sometimes, he slept in his car between jobs. Then he was hospitalized for exhaustion and a staph infection.

“While people around me praised my hustle, I eventually paid the price,” Stewart said. “The doctor looked at me and said, ‘I don’t know what lifestyle you’re living, but you’re too young to be this stressed. You’re going to have to quit something.'”

So Stewart, now 36, began setting boundaries. He gave up the side jobs, deciding he could survive without extra income. If people from the news show texted him after-hours, he let them know he was off-duty and where else to call.

Setting boundaries at work, and in life, can be tricky. Many people find it difficult to say no, especially to a manager. Some get a sense of satisfaction from being needed or pleasing others.

But learning to turn down a request or invitation is essential for protecting our physical and mental health, experts say. And as with any new skill, drawing boundaries gets easier with practice.

Experts in well-being and organizational behavior, along with other workers, shared strategies for setting limits.

Schedule aggressively

Adding tasks to your calendar may seem counterintuitive if scaling back is the goal, but can provide more control over your time.

Bobby Dutton, the founder of event production company GBM6, uses a technique he calls “aggressive calendering.” He schedules the task he’s most likely to procrastinate on, such as handling contracts and invoices, for every Monday at 2 p.m. To keep his calendar from becoming overloaded, he also books time for recurring routine tasks like making coffee, walking the dog and eating lunch.

Write a script

If you’re unaccustomed to saying no, you can write down what you’re going to say beforehand and rehearse it. Stewart worked on letting colleagues know when his assignment load began feeling too heavy with phrases like “Hey, this is a lot for me” or “You gave me seven stories, I think I can get four or five done.”

Cara Houser, a workplace engagement coach, says you don’t have to explain yourself when declining a request. You can simply say you’re not available at that time, followed by “Thanks for asking, and I hope to have more capacity next time.”

If the recipient of your “no” tries to argue, you can respond, “I hear you feel that way. But for me, this is what I’ve decided to do for that day,” Houser said.

Entrepreneur Amber Krasinski grew up in a working-class environment where saying no to a boss could mean losing a paycheck. As the founder of marketing company IvyHill Strategies, Krasinski worries she’ll lose clients if she turns down a project. “Not yet” is her go-to phrase when one more project is too much.

“That phrase has helped me through a lot of situations,” she said.

Know your limits

It can be tempting to agree immediately when we’re asked to chip in. But there may be times when we’re better off demurring. When faced with a new work request, take five minutes to assess your workload, energy level and priorities before responding, suggests Israa Nasir, a psychotherapist in New York.

Nasir says a former boss frequently texted work-related questions at 10 p.m. on Fridays and Saturdays. “I didn’t say, ‘Don’t text me,'” she recalled. “I said, ‘Can we check in on Fridays before the weekend? So everything that’s on your mind, you can (tell me) and then I can plan my time accordingly.'”

Pay attention to the activities and interactions that leave you feeling drained or overwhelmed, Nasir said. Put those kinds of events on a “No List.” The list doesn’t mean you decline every time you’re asked, but don’t say yes right away, she advises.

Harness technology

Mobile devices make it easier to work from anywhere, and harder to draw boundaries. But there are ways to adjust our devices so they’re less distracting.

After noticing that she checked email far too frequently on weekends, Nasir starting moving the Gmail app from her iPhone’s homepage to the second page from Friday night to Sunday night.

An email signature is another tool you can use to manage expectations, by publishing working hours or upcoming vacation schedules, said Candice Pokk, a senior consultant in organizational effectiveness at Segal.

Pokk includes a “Well Being Notice” at the bottom of her emails which reads, “Receiving this email outside normal working hours? Managing a work-life balance is unique for everyone. I have sent this email at a time that works for me. Please respond at a time that works for you.”