On New Year’s Eve 2015, Grant Medsker Finalized a big decision. He was going to quit his job.

Days later, though he wasn’t scheduled to work, the 19-year-old barista took the 51 bus from his Lake City apartment to the Fourth and Seneca Starbucks, stepped into the back office, sat down, and drafted a handwritten letter to his boss. He gave two weeks’ notice.

Starbucks had transferred Medsker to the popular location six months earlier, luring him with 40-hour weeks, advanced training, and a possible promotion, he says, to become a trainer himself. But the hours became erratic and unpredictable. Some weeks he only logged eight.

He’d threatened to quit before, after his two-week paycheck only totaled about $200, leaving his girlfriend to cover their $1,050 rent and utilities. But his manager talked him out of it, saying they needed him.

He stuck around for weekend shifts, but those shifts, too, were haphazard and he was only getting four or four and a half hours instead of eight. Worse, he couldn’t even recoup his transportation costs, which sometimes included a $40 cab ride when he had to open before the buses started running or he needed a quick lift to make it in time for a last-minute work request.

A lot of service workers like Medsker are feeling the pinch right now, and scheduling rights are Seattle’s next big labor battle. More than 70 percent of workers between ages 26 and 32 report fluctuating hours—with 50 percent of that same group reporting a weekly change of more than eight hours compared to their supposed schedule. And over 40 percent of hourly workers know their schedules just a week in advance.

The issue is currently in front of the Seattle City Council; council member Lisa Herbold has held two public hearings on it. “We aren’t considering these policies because we think it’s a nice thing to do,” she says. “We’re actually trying to respond to changing labor conditions that are causing a greater amount of uncertainty for workers.”

The city’s push to regulate scheduling may spur an even more intractable debate than the minimum wage. At issue is the service economy’s business model. A new trend in hourly-wage work known as “just in time” employment, where management calculates labor-to-demand ratios, has become so sophisticated that bosses now manicure hours to maximize efficiency by mixing and matching truncated schedules to fill every hour of the workday.

That system also relies on employing extra-large staffs so managers have workers to choose from at all times. The practice empowers management to be flexible, but makes schedules unpredictable and workers expendable. It also allows management to skimp on benefits reserved for full-timers, or, as Medsker noticed at Starbucks, on giving employees lunch breaks; baristas earn lunch breaks at five hours. (For the record, Starbucks provides benefits starting at 20-hour workweek.)

Just-in-time scheduling “views workers as equipment,” University of Chicago professor Susan Lambert, who wrote a 2014 report on precarious work schedules, told me. Store managers are carrying out dictates of upper-level management to stay within the bloc of hours the company allots each store. “Fear is driving a lot of these problematic scheduling practices,” Lambert told council member Herbold’s civil rights committee in March. “Managers are afraid of going over.”

San Francisco has the only comprehensive law in the country regulating scheduling. The law requires businesses to tell workers two weeks in advance exactly what their schedules will be and makes companies compensate workers with half-time pay for abrupt changes like getting sent home early. The measure also addresses overhiring by making management offer current employees available hours before hiring new staff. Calling for “secured scheduling,” local labor-backed group Working Washington wants Seattle to pass similar regulations.

Secured scheduling doesn’t have the same visceral appeal as “15 Now”—Working Washington’s winning mantra during the minimum wage fight. But it may be more important to workers.

“A living wage is wonderful,” Darrion Sjoquist, a Starbucks barista at the MLK and Rainier Avenue store says, “if you’re working enough hours to make a living wage.” And Melanie, a barista at the Fifth and Columbia Starbucks, notes a compounding problem with erratic schedules: “If you can’t get full time at one place, and the schedule [there] prevents you from getting another job, then [the $15 minimum wage] does you no good.” Both baristas have signed on to Working Washington’s campaign; Sjoquist in fact stood up and publicly challenged Starbucks CEO Howard Schultz about the issue at the company’s annual shareholders meeting in March. (The coffee giant recently reaffirmed its policy to set schedules two weeks in advance.)

Sejal Parikh, Working Washington’s executive director, agrees the issue is a bigger deal than her group’s original signature campaign. “The $15 minimum wage was about money, but secure scheduling is about power.”

At a fast food business like Domino’s, minimum wage workers don’t get their schedule for the following week until Sunday night. They’re nice enough to send it by email, though, laughs Crystal Thompson, a Domino’s employee. A single mom who pays $1,105 rent at her Rainier Avenue apartment, Thompson says she has little choice but to cooperate. “I need the money to pay the bills,” she says, “so I take the hours I’m given.”

Thompson, 34, has been working at the Domino’s on Rainier for seven years. Scheduling, she says, varies “from manager to manager,” which throws off her ability to take care of her two boys, a nine-year-old and a two-month-old.

Hourly workers are disproportionately minorities and women. Seventy percent of nonwhites are hourly workers, while 62 percent of women are hourly workers. Further, a startling 90 percent of food service workers report that their hours fluctuate by an average of 68 percent when judged against their usual hours. “One day I might be working during the day and the next day I might be working at night,” Thompson told me over the phone—and over the cries of the infant sitting on her lap. (Domino’s did not return my calls.)

Thompson, who takes food orders, makes pizzas, dispatches drivers, and mops the floors, says “not seeing the schedule until Sunday night…and trying to find child care” has forced her to rely on her mom and her aunt. “If I didn’t have my family…” she says, trailing off.

When her family isn’t available? It’s on Thompson to get someone to cover.

Of course flexibility is a two-way street. David Jones, who runs two Seattle Subway shops, says, “The most attractive thing about the restaurant industry [for employees] is the flexibility of being scheduled one week ahead.” Employees, he says, are the ones regularly requesting last-minute changes. The demand for two weeks’ advance notice on scheduling, he argues, is “a sound bite from the union that’s not reality in my restaurants.”

Jones worked his way up from the bottom of the industry 30 years ago and now, in addition to running a batch of Subways, owns the suburban chain Blazing Onion. He says penalizing businesses for scheduling changes isn’t fair, because, for starters, some employees aren’t comfortable asking coworkers to pick up shifts, so that task falls on the manager. “Should I be penalized for making that scheduling change?”

And the industry is uniquely unpredictable. A restaurant might be hit with a party of 30 after a soccer game, and a manager might need to ask staff to stay later—or send people home early because there’s a giant storm or employees show up sick. That manager, Jones maintains, should be able “to make the call.”

Working Washington agrees that employees like flexibility but believes they should be able to make the calls, too, that flexibility is as much about changes in employees’ lives as late-breaking changes in business. When management has all the power, employees’ lives don’t seem to matter.

In fact, they barely register. After Grant Medsker left his handwritten note in the Starbucks back office—he eventually landed a full-time job selling cars in Lake City—he never heard from his manager again. “She never acknowledged the two weeks’ notice.”

After he left the note, Medsker decided to walk to another Starbucks, at Third and Pike, to tell his girlfriend the good news. She works for Starbucks too.