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The traditional eight-hour workday may soon be the exception rather than the rule. New evidence shows that we’re reaching a tipping point in terms of workplace flexibility, with businesses seeing the wisdom of allowing employees — young ones especially — to work odd hours, telecommute and otherwise tweak the usual 9-to-5 grind.

One of the top 12 trends for 2012 as named by the communications firm Euro RSCG Worldwide is that employees in the Gen Y, or millennial, demographic — those born between roughly 1982 and 1993 — are overturning the traditional workday.

The Business and Professional Women’s Foundation estimates that by 2025, 75% of the global workforce will be Gen Y. As early as next year, this group of younger Americans will comprise 60% of the employees at companies like Ernst & Young. And increasingly, companies are creating workplace-flexibility programs because it makes good business sense, not in the least because that’s what their employees are demanding.

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Gen Y-ers are spearheading this change because they don’t want the same work environment their parents had. Between new technology and global workplace dynamics, companies are implementing flexible work arrangements for everyone, inclusive of Gen Y. A recent Vodafone U.K. survey illustrates that 90% of employers enable work flexibility instead of sticking to traditional hours.

Leading the charge in the shift toward allowing employees to work anywhere around the world, at any time they want, are companies such as Ernst & Young, Aflac and MITRE, which all realize that they need to accommodate employees’ personal lives if they want to retain them. “This notion of an eight-hour day is rapidly disappearing, simply because we work so virtually and globally,” says Maryella Gockel, Ernst & Young’s flexibility-strategy leader. By understanding Gen Y-ers’ need for workplace flexibility, companies are better able to recruit and grow young talent for the future.

Aside from the early adopters of workplace-flexibility programs, many other companies are hesitant because of the traditional “command and control” approach laid out for older generations. The challenge these companies face is letting go and trusting their young employees — even when they are telecommuting or using Facebook regularly at work.

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Many companies fear that, without structure, employees will be distracted, not as engaged and less productive. In fact, the opposite is often true. A trusting work environment breeds more-loyal employees and increases efficiency. Here are three reasons for companies to embrace workplace-flexibility programs:

1. Gen Y workers won’t accept jobs where they can’t access Facebook. Cisco’s “Connected World Technology” report shows that more than half of Gen Y employees prioritize social-media freedom over a higher salary when evaluating a job offer. Furthermore, more than half say the Internet is an integral part of their lives. Gen Y-ers wants to be connected to their friends and families, not just their co-workers, throughout the day. Although some companies ban social media at work, other companies have embraced it as long as employees use it professionally. “We do want people to use social networks in order to keep in touch with their colleagues and contacts,” explains Gockel, whose company has no formal social-media guidelines or policies. Cisco’s “Connected World Technology” report shows that more than half of Gen Y employees prioritize social-media freedom over a higher salary when evaluating a job offer. Furthermore, more than half say the Internet is an integral part of their lives. Gen Y-ers wants to be connected to their friends and families, not just their co-workers, throughout the day. Although some companies ban social media at work, other companies have embraced it as long as employees use it professionally. “We do want people to use social networks in order to keep in touch with their colleagues and contacts,” explains Gockel, whose company has no formal social-media guidelines or policies. (MORE: The Blackberry Moral, Or: The Trouble With Too Many Options) 2. Gen Y-ers value workplace flexibility over more money. More than one-third (37%) of Gen Y workers would take a pay cut if it meant more flexibility on the job, reports a study by Mom Corps. Flexibility motivates these workers to be more productive and loyal to their companies because they feel like they are respected. An employer that allows flexibility in the workplace also demonstrates that it understands the evolving modern-day work environment, which bodes well for the future.

3. Gen Y workers are always connected to jobs through technology. Technology has made the traditional 9-to-5 model blurry — for all workers, of all generations, really. No one is ever out of touch or off the clock. When workers go home, they’re still working because who they are personally and professionally have become one and the same. Workers are always representing the company, and more and more, it seems, work e-mail doesn’t stop for anything or anyone. By no means does time away from the office equal less work getting done.

Schawbel is the managing partner of Millennial Branding LLC, a full-service personal-branding agency. He is the author of Me 2.0: 4 Steps to Building Your Future, founder of the blog Personal Branding and publisher of Personal Branding magazine.