More than a decade ago, David Gross was just your typical Bay Area dude. He worked as a technical writer for a software company and made around $100,000. He enjoyed nice meals out, and he spent what time he could exploring, going to Burning Man, or watching old game shows on TV.

Then the U.S. invaded Iraq, and Gross had what was probably a pretty typical Bay Area reaction: He didn't agree with the war. But for Gross, who is now 44, this opposition turned visceral. Even though he was going to anti-war protests and speaking about his opposition to the war publicly, he couldn't sleep. He had trouble looking at himself in the mirror.

So he did the only thing that he thought might make him feel better: He went to his company's HR department and asked for a 75% pay cut, which would help him avoid paying federal taxes, and make sure his money wasn't going to fund the war.

They said no.

Rather than continue working, Gross embarked on a drastic lifestyle change. He quit his job, and started working as a freelancer, earning enough to make a modest living, but little enough to avoid paying federal income taxes. He now works about 500 hours a year. If he followed a 40-hour work week (which he doesn't), that would mean he toils about three months out of the year.

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Around 43% of U.S. households pay no federal income tax, down from 49% in 2009, according to the Tax Policy Center. Usually, families don't pay the tax because they haven't earned enough money over the course of the year, and are struggling to pay the bills. Some work all year and still don't earn enough to pay taxes. Gross knows he's lucky to be able to make the choice to earn so little. But it's made his life better, he says.

"I was cheating myself by spending all those hours at work," he told me recently, a decade after he started this lifestyle. "Now, I've learned the benefits of living a simpler lifestyle, having more free time, spending less time as a nine-to-five worker."

Gross is one of dozens of young activists who have pared down their lives, shed their possessions and quit their day jobs to live more simply.

There's Jacob Lund Fisker, who in 2010 published Early Retirement Extreme, which outlines a way to live more frugally (on around $7,000 a year), save money and get out of working a nine-to-five job. There's Rob Greenfield, an environmental activist with few possessions, who recently embarked on a cross-country bicycling tour eating only food he found in dumpsters and bathing with lake and river water. There's Glenn Morrissette, a forty-something composer who now travels around the country in a van to avoid "careless consumerism" and blogs about it.

In another time, these guys might have been called hippies, a term that conjures images of naked, long-haired men living off the land. But these guys very much have their act together, and there are parts of the real world that they don't eschew. Morrissette, for instance, still writes music, and even orchestrated an episode of "Family Guy." Fisker and Greenfield both pursue interests that are part of "The Establishment," as the hippies might have called it. Fisker owns a house (he paid cash), races yachts, and invests in the stock market. Greenfield still runs a marketing company, and was in talks with Ryan Seacrest's production company to host a TV show.

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When he first started his experiment, Gross assumed he'd have to live in poverty to avoid paying federal taxes. He thought about living in a fire spotting tower to pay the rent, and resigned himself to a life of rice and ramen, and "a path of deprivation, sacrifice, and renunciation in the service of my values," he wrote, in an essay on Shareable in 2012.

But then he started doing some research. He knew he wanted to set aside some money for retirement, and that he could probably find enough contract work to earn as little or as much as he wanted, up to the salary he had been receiving.

Because he wasn't married, had no dependents, and put a good chunk of his money -- about 40% -- into IRAs and health savings accounts, he discovered that he could make $36,000 a year and still avoid paying federal income taxes.

After the money was taken out for the retirement and health savings, Gross was left with about $20,000 a year. None of that went to Uncle Sam.

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It's still not a whole lot of money, especially in San Francisco, where the average rent in October was $3,413 a month, but Gross made it work. During the early years, he split a one-bedroom apartment with his then-girlfriend, and each paid $500. He started cooking meals from scratch and shopping at farmer's markets, and brewing his own beer (which also helped him avoid federal excise tax on alcoholic beverages). He started going to the library more and exchanging skills with people -- teaching them web programming if they'd teach him about meat curing. He bought stuff used, or got it on Freecycle.

It wasn't as hard as he thought it would be, Gross says.

"For most people, when your salary rises to a certain level, your expenses rise along with it," he said. "So when you imagine working not quite so much, you just think, 'Where would I get that money?' My recommendation -- start paring down, start simplifying, squirrel away that money that you're spending."

The amount of money Americans can earn and still avoid paying income taxes varies by their deductions, marital status, and expenses. In 2014, for example, a single, non-blind person under 65 with no dependents, who didn't put money into retirement or health funds, could earn $10,150 without paying any income tax, according to the National War Tax Resistance Coordinating Committee. But, as Gross figured out, you can earn a lot more than 10 grand if you can take deductions for things like commuting expenses and tuition fees, which reduce your taxable income, or if you put money into health savings accounts and an IRA.

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I was curious about Gross's financials, but even more curious about what he did all day. After all, even the richest Silicon Valley entrepreneur, who doesn't have to work another day of his life often gets restless. Even if he doesn't miss the money, doesn't Gross get bored?

Nope.

"I think I take that sort of pleasure from a variety of things now rather than a single thing," he said. "If there was one thing that excited me, I would still be able to do that, potentially, if it didn't earn any income, but as it is, I like having a diversity of interests, move from thing to thing as it strikes me."

Gross now lives in San Luis Obispo, in central California, near his parents and with his brother, who works a more conventional job. He isn't married, and doesn't have kids -- and doesn't plan to have them. Instead, he spends his time writing and researching projects he's interested in: a book compiling the political writings of Henry David Thoreau, a compilation of works about American Quaker war tax resistance. He participates in a weekly discussion group modeled on Benjamin Franklin's Junto club for mutual improvement, and has a group of close friends he spends time with. He cooks a lot -- meals that he says are as good as the ones he would spend money on when he lived in San Francisco, in the days before he decided to change his lifestyle.

"It seems that many things people give up to pursue their careers are more valuable than the money they gain in the trade," he wrote, in the essay about his choices. "And many are not for sale at any price: health, youth, and the time we need to pursue our dreams, learn new skills, volunteer for good causes."

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Gross says that some years, he does his 500 hours of work in one big push, and others, he spreads it out over the course of 365 days, working a little here and there. When he's not working, he sometimes travels -- but by bus or train, rather than car or plane, and when he goes out of the country, to vacation in Mexico, for instance, he stays in hostels and eats cheaply.

He's still active with the war tax resistance movement, and goes to its meetings, which occur twice a year. And he meets people all the time who are also seeking a more simple life. Some don't want to contribute to pollution or drive the oil economy, some want to spend more time with their families, some "don't want to be on the treadmill for a huge chunk of their lives," he said.

And some, like Gross, just wanted to live a different way, which is not necessarily that strange. After all, it was Henry David Thoreau, whose works Gross compiled in his free time, who went to live in a cabin in the woods of Walden Pond in 1845, spending just $28 for a home and some land on which he could grow his own food.

"The mass of men lead lives of quiet desperation. What is called resignation is confirmed desperation," Thoreau wrote. "Most of the luxuries, and many of the so-called comforts of life, are not only not indispensable, but positive hindrances to the elevation of mankind."

This article originally appeared on The Next Economy, a joint project of The Atlantic and National Journal.