There’s a growing demand for on-demand jobs.

The gig economy, which includes the freelance workers driving your Uber, doing your Task Rabbit chores or hosting your Airbnb, is expected to double to 9.2 million people over the next four years.

In fact, Intuit and Emergent Research reported last week that these on-demand jobs will make up 43% of the workforce by 2021, which is more than the current number of full-time workers in finance or construction. There are already more gig workers hustling than people employed in the entire information sector (including publishing, telecommunication and data processing jobs) and IT services combined, according to the Bureau of Labor Statistics.

The Netflix comedy “Unbreakable Kimmy Schmidt” has even shown the title character trying to make ends meet in NYC by working for TaskRabbit and driving an Uber.

Freelancers told Moneyish that this gig work empowers them by making them their own bosses.

“You’ve got flexible hours, unlimited vacation and time to do other projects,” said Matthew Ernst, 29, a Manhattan personal trainer.

But while he’s benched as much as $12,000 on a good month, he’s had slow seasons – like summers in the city when clients are away on vacation – when he’s only made $1,000 or so.

“It can also be long, odd hours, since you’re training people before and after they get out of work at their day jobs,” he said. “And I’ve got to pay for my own health insurance.”

“Unbreakable Kimmy Schmidt’s” Titus and Kimmy have worked plenty of on-demand jobs on screen. (Eric Liebowitz/©Netflix/Courtesy: Everett Collection)

Brittany Sherwood, 27, is a psychiatric nurse practitioner juggling three different gigs, including working for the Maven health app giving video and telephone consultations from her home office.

“If you’re not grinding, if you’re not hustling, then you don’t feel like you’re doing enough,” she said, noting she has no idea how many hours she works a week. “There is this perpetual anxiety about finding work and getting enough bookings.”

But despite the stress of never knowing whether she’s going to make $1,400 or $12,000 from one month to the next, she enjoys making her own hours. “Flexibility was a big part of doing this virtual work,” she said, “because my partner and I are talking about moving to Amsterdam, and I don’t want to be tied down.”

Some independent contractors do gig work on the side of their day jobs to bring in some extra cash, or fulfill a creative ambition. The average person working an on-demand job spends 11 hours on it per week, and 41% still hold down a traditional full-or part-time job.

“You’re not making enough at your job, and you need more money than that to live,” millennial career and workplace expert Dan Schawbel told Moneyish. “So you look for additional income somewhere, and freelancing is there for you.”

And employers are also embracing the freelance workforce because they don’t have to worry about covering a contract worker’s health care, life insurance or 401K.

“Employers are trying to do more with less, and one way they get around that is to hire freelancers,”  said Schawbel. “They don’t have to give them benefits, and they know they can fire them at will.”

But there’s downsides for employers too, since freelancers are not as loyal as full-time staffers, and they divide their time among several clients. That’s why Schawbel predicts we’re not going to see a decrease in full-time employment in the future, but rather a blended workforce with “an increase in both full-time employment and freelancers.”