The beauty of Office 365 is that you get more than just Office 2013 for your money--it also comes with benefits that Office 2013 lacks. It comes with an additional 20GB of SkyDrive storage and 60 minutes per month of international Skype calls. Office 365 also has a new feature called Office On Demand that enables you to stream virtualized versions of the full desktop software to any Windows 7 or Windows 8 PC.
But, even for other platforms or mobile devices there are Web-based versions of the Office applications, and as long as you store your files in SkyDrive you can access them seamlessly from virtually any Web-connected device. The world doesn't end if your laptop is stolen or destroyed, and you can still edit a crucial client presentation even if you don't have your PC with you.
Even if you only need the applications in Office 2013 Home & Student, it would cost $700 to put that software on five machines, and it would take seven years to break even on the cost of the Office 365 subscription. By that time, there will be a new version of Office (or two, maybe three). If you buy Office 2013 Home & Student, you'll still have it in the year 2020. But, if you subscribe to Office 365 you will always have the most current version of Office available.
Microsoft has set things up so that the decision is already made. You are free to purchase Office 2013, but Office 365 has very clear advantages, and it makes more sense financially in almost every scenario.
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