In 1974, Ahmad and Ann Shirazi moved into a rent-stabilized apartment on Manhattan’s Upper West Side, though at $275 a month, the rent felt high for two bedrooms.

The Shirazis hoped to have children and thought their stay would be temporary. Nearly 50 years later, they are still there, after raising two children in a space they made work because it was affordable.

The story of the Shirazis — Ahmad, 84, a retired film editor who worked on the movies “Scarface” and “The Bonfire of the Vanities,” and Ann, 78, who worked as an illustrator for department stores like Henri Bendel — reflects the experience of many the city’s roughly two million rent-stabilized tenants, almost a quarter of the city’s total population.

As New York City became one of the most expensive places in the nation, apartments with regulated rents and guaranteed lease renewals offered a reprieve to the working and middle class: The Shirazis now pay $1,025 a month, while a similar unit in their building, which is not stabilized, rents for more than $5,600.

On Wednesday, the city’s vast stock of rent-stabilized homes, which has come to be one of New York’s most important sources of lower-cost housing, is about to become a little more expensive. A New York City panel is set to let rents in the city’s one million rent-stabilized apartment rise for the second consecutive year, citing high inflation and ballooning costs for property owners.

Last month, the panel, known as the Rent Guidelines Board, backed increases on one-year leases of between 2 and 5 percent and increases on two-year leases of between 4 and 7 percent, in a preliminary vote.

It would be the second time during the tenure of Mayor Eric Adams — who appoints members to the panel and who has expressed sympathies for the difficulties facing landlords — that the Rent Guidelines Board would allow stabilized rents to increase. Last year, the panel voted to raise rents on one-year leases by 3.25 percent in rent-stabilized homes, and on two-year leases by 5 percent.

The Shirazis, who earn about $4,500 a month in retirement benefits, will find a way to manage, they said. They and several other renters across the city — including higher earners, retired people who had lived in their apartments for decades and newcomers — said that incremental increases has helped them find stability in New York City’s otherwise chaotic and unforgiving housing market.

But many also said the moment also reflects something deeper: how people of modest means are finding it harder and harder to live in New York City.

As expensive as it is to live in New York, no other American city has a rent regulation system as vast: More than one million apartments — half the rental market and almost 30 percent of all of New York City’s homes — are covered by a system begun in 1969.

The majority of rent-stabilized homes are in buildings built before 1974. For many years, the number dropped, as landlords moved to leave the program and get more income from higher rents.

Since 2017, however, the overall number has grown, according to a tally of units registered with the city and state, particularly as many new units and rehabilitated units became rent stabilized in exchange for tax breaks or subsidies.

While many of the newer units rent at a higher rate, and there are no income restrictions associated with rent-stabilization, the system tends to benefit people of lower incomes.

The median household income in rent-stabilized apartments was $47,000, compared with almost $63,000 in private, unregulated units, according to a 2021 city survey. The median rent in stabilized apartments was $1,400, compared with $1,825 in private, unregulated apartments, according to the survey.

The city’s “economic diversity is premised on rent stabilization,” said Samuel Stein, a housing policy analyst at the Community Service Society, a nonprofit group that advocates for lower-income New Yorkers.

But now, the future of the program is less clear.

In the wake of rent laws passed by left-leaning state politicians in 2019, property owners say they feel beleaguered and unable to make renting stabilized apartments financially viable.

A group of New York City landlords has petitioned the U.S. Supreme Court to undo the regulations, a case that has drawn the interest of a variety of business groups, including the U.S. Chamber of Commerce, who are eager to see rent controls repealed or eased nationwide.

Michael Tobman, the director of membership and communication for the Rent Stabilization Association, an industry trade group, said the system forces private owners to provide a public benefit.

“All they have are escalating costs, and this piece, increases from the Rent Guidelines Board — that’s desperately needed,” he said.

The mayor has defended the panel’s approach as a way to protect mom-and-pop landlords, sometimes noting that he himself is a small landlord, even as he has called for the panel to steer away from the highest increases.

“We simply cannot put tenants in a position where they can’t afford to make rent,” he said last month.

But many landlords of rent-stabilized buildings are big companies. They include developers like Cammeby’s, Lefrak and L&M Development, who each have several thousands of rent-stabilized units in their portfolios, in addition to market-rate units. The companies either declined to comment or could not be reached.

John A. Crotty, founding member of the Workforce Housing Group, which has about 1,500 rent-stabilized homes in its portfolio, said increases were justified because during the tenure of the previous mayor, Bill de Blasio, the panel largely rejected major increases, placing landlords in a difficult position.

“When you fall below the real cost line, and then you have a period of hyper inflation, how is this any kind of good?” he said. “No matter how big of an increase Adams does, it won’t be enough.”

Peter Madden, the executive director of Westbeth Artists Housing, which has about 383 apartments in the West Village, the vast majority of which are rent stabilized, acknowledged the pressures facing property owners.

But he also said rent stabilization was the “largest, best affordable housing program the city has.”

At Westbeth, which also receives some subsidies from the city, rents on stabilized homes range from less than $1,000 to $2,300 for a three-bedroom.

“If not for rent stabilization, I don’t know how folks would do it,” Mr. Madden said.

For some tenants, rent stabilization is a lifeline, particularly as the city experiences one of the most brutal rental landscapes in recent memory during a rebound from the worst of the pandemic.

The 2021 survey found that one-third of New York City tenants spent more than half of their income on rent. For them, looming increases will force difficult choices about where else to cut back on spending.

“A rent increase this year for me would be like $80 more each month,” said Chen Ren Ping, 65, who shares a rent-stabilized apartment in Chinatown he has lived in since 2004. “If we didn’t have to pay those $80, we would eat better, our lives would be better, we would have an improved quality of life.”

Mr. Chen said he earns about $794 a month in social security payments. But he said his half of the rent for the two-bedroom apartment is $800, so he does repairs around the neighborhood to supplement his income.

Ann Shirazi said she was not happy about the coming increase for her own household. She also worries about the future of the city.

“It was a beautiful place to raise our kids,” she said. “And now because of the wealth, in my view, it has completely changed.”