Anne Marie Bowler left work one day last week to enjoy dinner with a friend at a sidewalk café "before the sun went down," she says. Recently she ducked out of the office to attend a charity golf outing. And Ms. Bowler also likes to make time for long evening bike rides through Central Park.

She could never have done these things at her old job.

Ms. Bowler worked 9 a.m. to 9 p.m. or later at a big law firm in New York City for years. The daunting workload often forced her to cancel plans with friends or time at the gym, and she yearned for more control. At age 30, she and a colleague who had just returned from maternity leave quit to start their own law firm.

Being single takes a lot of time. There's no one else to pick up milk or take out the recycling on the right day or wait at home for the plumber. It's just you. Sue Shellenbarger explains on Lunch Break. Photo: Bryan Derballa for The Wall Street Journal.

She is still immersed in clients' cases and often works long hours. But "I wanted to have a life—a full life—which meant not just always working," says Ms. Bowler, now 36.

It's the refrain of millions of working mothers across the country who exit fast-track careers in their 30s. But Ms. Bowler is single.

Much of the research on work-life conflict focuses on harried working mothers trying to juggle everything, desperate for more time, with lots of reasons to leave work early. But an even higher proportion of single women yearn for more free time; 68% of childless women say they would prefer having more time over more money, compared with 62% of women with children, according to a 2011 More magazine survey of 500 college-educated professional women over 34.

"People talk about, how do working mothers do it? But how do singles do it?" says Sherri Langburt, founder of SingleEditionMedia.com, a New York agency that advises brands on marketing to singles and runs a network for bloggers on singles topics.

On the way to work, she stopped at a local coffee shop, where she could also spend time catching up on email. Bryan Derballa for The Wall Street Journal

Work & Family Mailbox Columnist Sue Shellenbarger answers readers' questions

Without a partner to help, singles must "get the laundry done, get to the gym, buy groceries and get to the job," plus plan social activities or volunteer work and sometimes care for aging relatives, too.

"No one is focusing attention on those women or men, who are achieving such great levels in their careers, all alone," Ms. Langburt says.

As more young adults delay marriage into their 30s while career demands intensify, many increasingly feel overloaded. Many set high expectations for themselves, dating, staying in shape, doing volunteer work, and helping family—while still getting stellar performance reviews.

Conflicts with child-rearing duties are often cited as the reason large numbers of women quit corporate jobs midcareer. But many single women without kids also consider quitting for personal reasons. In a recent McKinsey & Co. study of 60 companies for The Wall Street Journal, researchers surveyed a small sample of women who were planning to leave their companies in the next two to three years and found surprising similarity between reasons cited by mothers and non-mothers—a desire to gain more control over their personal schedules and needs.

When it was time to go, she rode her bike to the law office she and a co-worker started so they could have more work-life balance. Bryan Derballa for The Wall Street Journal

Even though she left the big law firm, Ms. Bowler still takes late-night and early-morning calls and handles complex litigation. On a recent golf outing, she checked and sent email every hour and called her voice mail twice.

But "my schedule is much better. I've made it better," she says. She has freedom to attend more professional networking and education events, and to explore new areas of the law that interest her, including a seminar this summer on fashion law.

She travels more, including vacations to India and Brazil. And she enjoys being able to "have a steady schedule, making social plans with people and keeping them," says Ms. Bowler. On days she and her partner, Sari Gabay-Rafiy, leave the office before dinner, "We say, 'Oh, it's five o'clock. That used to be snack time' " at their former law firm.

Juggling Non-Work Duties

Single professionals report going to extremes to manage non-work duties—buying extra socks and sheets to avoid doing laundry, cooking and freezing 20 meals at once to save time or jamming two or three workouts into the weekend to try to stay in shape.

A 37-year-old New Jersey project consultant with an active social life says she faces piles of dirty dishes, laundry and unanswered mail when she gets home each evening, and she can't get started on important financial planning.

Married friends 'are always asking me for my fun New York City gossip and my "Sex and the City" lifestyle,' says Melissa J. Anderson. But that 'is not exactly the case.'

"Some of my friends who are married or in long-term relationships are always asking me for my fun New York City gossip and my 'Sex and the City' lifestyle," says Melissa J. Anderson, 29, a website editor who lives in Brooklyn. But that "is not exactly the case."

She commutes an hour round-trip to her job, where she puts in a 10-hour workday, and attends work-related events several evenings each week. Weekends, she volunteers at an AIDS charity, works a few more hours and squeezes in time at the gym. She recently dined on beans and rice for a week because she couldn't make it to her neighborhood grocery store before it closed at 8 p.m.

Employers Taking Steps

Many employers have added "work-life benefits," such as flexible scheduling and personal time off, in an effort to keep all kinds of employees happy, with and without kids and spouses.

But the benefits only go so far. Heavy workloads keep many employees from using them. And for men and women alike, some managers still assume singles don't have anything to do but work and pile on extra duties and projects, according to research by Wendy Casper, an associate professor of management at the University of Texas at Arlington.

When Craig Ellwanger's former bosses hired him as an ad-sales representative in 2006, they were glad he was single with no kids, Mr. Ellwanger says. They told him in the interview, "We're going to ship you all over the place. Don't get too attached to any place or anyone." He spent half his time on the road, living in hotels or company apartments. Dating was difficult; his schedule "was definitely very taxing" for his girlfriend. "It was pretty much a long-distance relationship," he says. They married briefly then divorced, partly, Mr. Ellwanger says, because his job was so consuming that he couldn't separate the stresses from home life.

Resorting to Ramen Noodles

As pressure to increase sales kept mounting, "I was really becoming more irritable," avoiding social activities, he says. Battling insomnia, he stopped seeing friends and stayed home alone on weekends, watching football on TV and putting off laundry, grocery shopping and paying bills. Although he normally relishes cooking, he reverted to dining on ramen noodles.

Finally in January, he quit, telling himself, "I've got to do this before I go crazy."

Now, Mr. Ellwanger, 31, works full-time on an exotic-game website he founded for hunters and others to learn about and find different species around the world. The paychecks are smaller and uncertain. But he loves the work, and the balance with his personal life is far better. He visits family members more often and golfs with friends. He has resumed cooking meals for his friends, such as braised ribs, and hopes to resume dating. And, he says, "I'm sleeping like a baby."

Write to Sue Shellenbarger at sue.shellenbarger@wsj.com