Start now. Particularly if you skipped Vista, you need to start testing applications for compatibility with Windows 7. Microsoft says it will discontinue support for Windows XP in April 2014. Gartner predicts that many application vendors will drop support for XP versions by 2012. "Application support is the biggest problem to be concerned with," says Gartner analyst Michael Silver, even with some browser applications: Windows 7 forces an upgrade to Internet Explorer 8. \nTo read more on this topic, see: Windows 7: Why I'm Rolling It Out Early and Windows 7: Enterprise Features Explained.\n\nIt's a small step. While critics have likened Windows 7 to an overgrown service pack, City of Miami Assistant Director of Information Technology James Osteen Jr. sees that as a good thing. "It's not a total rewrite. It's really a more advanced version of Vista," he says. So he hasn't felt the need to wait before starting an aggressive deployment. "This OS has been rock solid since beta 1 in January," Osteen says.\n\nAnd a giant leap. Windows 7 improves performance, reliability and ease of use. Users tend to be most excited by basic things like the speed with which Windows 7 loads, sleeps and wakes compared to earlier versions, Silver says. But enterprises will value other features, such as Bitlocker encryption of hard drives and portable media. The city of Miami is projecting savings from better power management and user interface improvements that will lower support costs.\n\nNot everyone is convinced. Allan Hackney, CIO at John Hancock, says operating system upgrades rank low when it comes to delivering business value. He took eight years to roll out Windows XP. "Our deployment of Win7 can be the next guy's problem in 2017," he says, only half-facetiously. Silver notes that some companies may wish to wait until key vendors deliver Windows 7 supported versions of their products. SAP's Windows 7 client won't be available until spring.\n\nUsers may pull for it. Silver recommends deploying Windows 7 as part of the normal PC refresh cycle, but he also expects some Vista users to clamor for an upgrade. Osteen says Miami is doing in-place upgrades for the first time because of end user demand, rather than deploying the new operating system only on new PCs. Soon after the first desktop support and help desk personnel were given the beta, he says, others started asking, "when do I get to install this?"