Adriane Livers makes sure her boss has as close to a glitch-free work life as humanly possible. Each week, the administrative coordinator keeps the boss' schedule, screens calls and e-mails, books speaking engagements, travels to client sites, and manages a deskload of other responsibilities.

On Tuesdays, however, her duties are markedly different: Livers, 40, might sort through personal mail, pay household bills, visit the post office or bank. Often by midday, she gets an early start on dinner. Sometimes, she may work up a sweat over a tough job of the backyard variety.

No one, not even the boss, minds.

Livers, of Collegeville, works a four-day week. She takes off Tuesdays, but puts in nearly 10 hours a day the rest of the time at the Amoore Group, based in King of Prussia. Since May, the company, which consults on health and welfare-to-work, has offered the 4-10 - shorthand for a compressed workweek - to help staff with fuel costs.

As energy bills mount, more employers around the country, including municipalities, school districts and businesses, have adopted an abbreviated schedule. Many others are weighing the option, not only to ease commuting costs for workers and help the environment, but also to save on operating expenses.

Experts, however, give the model mixed reviews.

"We're watching very closely," Michael Littlejohn, vice president for human capital management at IBM, said of four-day policies, particularly in Utah. This year, Utah became the first state government to mandate the format for most of its workers.

Concerns revolve around productivity, customer service and employee morale - issues that cut both ways. For instance, while more work might be accomplished in a longer day, quality could suffer, studies show.

Over the next six months, almost one-fourth of 303 companies surveyed nationwide plan to offer, for the first time, a four-day option, the New York consultancy Mercer found.

The practice mirrors what happened in the 1970s during the Carter administration - another period when hard economic times resulted in energy conservation measures such as shorter weeks.

"It needs to be a conversation that all organizations ought to be having," said Rex Facer, an assistant professor at Brigham Young University in Provo, Utah, who studies alternative schedules. "We've got large and small, public and private and nonprofit going to a four-day workweek. . . . More and more organizations are asking questions. Does it make sense for us? Does it help us better serve customers and clients?"

Utah's experiment has helped reignite the four-day movement.

Since last month, most offices - and 17,000 employees - have kept a Monday-through-Thursday schedule of 7 a.m. to 6 p.m. On Fridays, the government closes. (Essential services, such as police and prisons, continue to operate 24/7.) Officials estimate the state will save $3 million in energy costs by shuttering 1,000 buildings an extra day.

Locally, Bucks County Community College, which for at least 25 years has truncated summer weeks for many departments, plans to look at adopting the practice year round, said Betty Hughes, who led a committee that explored the prospect. Under the plan, the school's offices would remain open five days, she said.

"Gas prices are driving it," Hughes said.

Even with recent fluctuations at the pump, gasoline is up $1.05 from last year, according to federal numbers.

At Philadelphia University, which has a 35-hour week, three-fourths of its 250 employees (faculty excluded) tried its new summer-hours pilot.

"That first week, those days seemed rather late," allowed spokeswoman Debbie Goldberg, who worked 7:45 a.m. to 5 p.m. "But when I got to Thursday, the skies opened, the sunlight came down."

Gloucester Township first closed on Fridays about 30 years ago due to that era's energy crisis. Since 1995, the township has operated five days a week with a staggered workforce. In July, it went back to closed Fridays. Mayor Cindy Rau-Hatton estimated that the energy savings over the fiscal year would be $22,000 to $30,000.

AAA Mid-Atlantic, based in Wilmington, saw the rise in fuel, food and other staples and decided to help employees by eliminating a day of commute with a new plan.

It wasn't purely beneficence, of course.

"Strategically, we believe satisfied associates result in satisfied customers," said Ron Gray, vice president for human resources and strategic planning for the auto club, which serves 3.7 million people.

Initially the program, begun this month, will cover 900 people - one-third of the workforce - to minimize any impact on customer service. The 4-10 schedule was the most popular. Employees also can work nine longer days and get the 10th off, or telecommute from home or another AAA site one day a week.

Reviews are enthusiastic.

"I really want this to work," said Wanda Quiles, 40, a single mother of two who lives in Mayfair.

She would love a 4-10 week but, like many working parents, cannot manage it. Quiles has to be out the door by 5 p.m. to collect the kids from child care, then oversee homework and dinner. Instead, she picked the nine-day schedule, which keeps her at her desk until 4:45 p.m. and will save her $60 a month in fuel and care charges.

Auto mechanic William Todd Hagan, 35, starts his day before dawn in order to clock in at 6 a.m. Ten hours later, at 4 p.m., he reverses his steps. The 4-10 saves him one day of a 200-mile round trip from his Auburn home in Schuylkill County to the Southwest Philadelphia AAA shop.

Even though he gets home after 7 p.m. on working days, "it's worth it to spend more time with my family," said the father of four, who took the children to an amusement park on a recent Friday.

Don't throw out the traditional day planner yet.

When businesses and governments close an extra day, "the servicing implications are tremendous," said IBM's Littlejohn.

Research also shows that "as we increase hours at work, we tend to make more errors later in the day," said Ray Gibney, an assistant professor of management at Pennsylvania State University in Harrisburg.

And 10-hour days - that can morph into 12 - can hurt on the homefront.

Brannon Dawkins works as director of communications for the Birmingham, Ala., Regional Chamber of Commerce, where 4-10 was offered for the first time over the summer. Employees can opt in on a month-to-month basis. After a summer of short weeks, Dawkins opted out for September. "It's really exhausting," she said.

Facer's research, however, shows that cities with four-day workweeks report higher levels of employee morale, more productivity, and lower levels of absenteeism.

Early in the industrial revolution, many workers toiled 14-hour days, six days a week, he said. The Fair Labor Standards Act of 1938 set the maximum workweek at 44 hours, motivated in part by the Depression and the need to spread out employment to more people.

"We've become quite accustomed to" a traditional week, Facer said. "That might not be the ideal schedule."

Alternatives often serve as recruitment and retention tools, employers say. Last month, West Chester-based QVC adopted a company-wide policy that allows for a compressed schedule, among other choices, as a way to attract the best and bolster its green credentials, spokeswoman Erin Mulholland said.

Back at the Amoore Group, chief executive officer Renee Amoore said the pros outweighed the cons.

"We have less people calling in sick, less people taking a personal day," she said. "They say they're feeling refreshed, even if they're working those 10-hour days."

Still, not all is perfect.

Amoore seriously misses Livers on Tuesdays despite a great substitute. "That's when I'm homicidal," she said, only half joking. "When she comes back, I have a pile of stuff on her desk."