"During peak times, when things are going well, employers are less impacted by productivity as far as people being off," Pancroft said.

Custom Blending Inc. of Fort Collins, Colo., for example, has only 14 employees — and when one takes a sick day, it affects almost everyone else.

"It's definitely detrimental to productivity," said Joe Basta, a partner in the company, which makes and distributes flavors, seasonings and other foodstuffs. "We have to shuffle to try and get that person's job done."

With the threat of a production slowdown, managers of the company — known chiefly for its line of Rodelle vanilla flavoring — will jump in and help on the assembly line if necessary, Basta said. Or they'll hire a temporary worker for a day.

"With manufacturing, it's not a question of, 'Hey, get it out when you can,' " Basta said.

Time-off and disability-program costs averaged 15 percent of employers' payroll in 2001 — up from about 14.5 percent the year before, according to Mercer Human Resource Consulting.

That means employers paid workers earning $40,000 a year, for example, about $6,000 for time away from work, or about 39 days of absence a year, according to the data, which came from a 2002 survey of 723 U.S. employers.

Many employers have begun switching to a "paid time-off bank system," giving employees a lump of time rather than splitting it between personal days, vacation and sick time.

When employees have the option of saving their time off for vacation, they tend to call in sick less, Pancroft said.

"You have to plan and manage the bank and hopefully anticipate you might be off for illness," she said. Companies "don't have to worry about the whole issue of whether your employees are abusing sick time."

Center Partners, a call center that employs about 600 people in Fort Collins, has a practice called "reality-based scheduling," said Chris Kneeland, chief operating officer.

On top of workers' vacation and sick time, employees also get eight hours a month for unpaid time off, she said. That encourages workers — many of whom are paid hourly — to schedule in advance to attend an early-afternoon soccer practice for their children or go to a dentist appointment.

"One of the things we try to do is make sure we can be flexible when people need time off, so that when we have work that needs to be done when other people are sick, they can stay and fill in," Kneeland said.

Facing higher productivity demands, more employees are taking disability because of stress or depression, according to the Mercer Human Resources survey.

Outsourcing specialist Celestica, with 600 employees in Fort Collins, uses a "paid time-off bank" and encourages employees to maintain a work-life balance, said spokeswoman Lisa Muenkel. "We don't want people to work sick, or work for a year and not ever take a vacation or be able to spend time for personal reasons," she said.