If the cloud has been universally accepted as a good idea, shouldn\u2019t it be an all-or-nothing proposition? One that lets you rely 100% on the scale, cost and redundancy benefits of one or more public cloud services?\nNot necessarily. Enterprises often adopt a hybrid of private clouds and one or more public cloud services. For example, you might look to cloud solutions as brand-new requirements emerge. Or you might consider public cloud resources for temporary, backup, or storage purposes. IDG\u2019s 2014 Enterprise Cloud Computing Study found that 19% of enterprises have deployed hybrid cloud environments.\nHere are a couple use cases where it makes sense to retain at least part of your own infrastructure:\n\nYou already have a bona fide data center. That probably means there are IT resources that need to depreciate and a real estate lease that needs to expire before you can cost-justify a whole new model. And if you\u2019re serving up legacy apps successfully from your data center, why change? You can virtualize some or all of your data center into a \u201cprivate cloud\u201d to get better server utilization. Then, as you grow your deployment or retire older resources, you can spill over into the public cloud.\n\n\nYou are in a highly regulated industry. Some industry compliance mandates require that certain data remain in a private data center. So you\u2019ll need to keep that data under your control, even as you look to public cloud services for non-regulated activities. Examples of directives that specify where data can and can\u2019t reside are the European Union Data Protection Directive and worldwide governmental regulations for finance, banking, healthcare and insurance.\n\nLet\u2019s say one or both of these situations exist in your organization. When might you extend your private data center\/cloud with public cloud services?\n\nYou have seasonal or other temporary work requiring a resource boost \u2013 compute power, development tools, and storage, for example \u2013 for a finite period of time. It makes financial sense to rent the resources instead of buying or building them. You pay only for what you use, instead of paying all year long for a peak volume that you need only now and then.\nYou have on-premise applications that could be enhanced by integrating them with content, data, or other apps available in the cloud. Or, you are using cloud applications that could be enhanced when integrated with data you have stored on site.\n\n\nYou need to deliver content all over the world to office sites and to mobile workers or customers. The cloud has points of presence in many locations, so you can get content closer to end users for better experiences. And cloud is the great equalizer of standard interfaces for serving a mishmash of mobile devices and operating systems.\n\n\nYou have an immediate competitive need to turn on a new app or service. Using a public cloud is the quickest route to completion.\n\nIf you are a startup with little IT infrastructure, you might have the luxury to start life using the public cloud as your complete infrastructure. Most organizations, though, will straddle their own internal infrastructure, often virtualized for greater efficiencies, and the resources public cloud service providers for some time to come.