Microsoft has a history of giving users a decent heads-up about when it will discontinue support for its desktop operating systems. That, however, can't be said about its mobile OS. But a keen eye at Plaffo.com found that Microsoft is changing its ways, indicating the exact date it will end its support for recent versions of Windows Phone. According to Microsoft's Support Web page, Redmond will end mainstream support for Windows Phone 8 on July 8, 2014. Windows Phone 7.8, meanwhile, will see its support run dry on September 9, 2014.
That gives both operating systems 18 months of standard and security updates. Of course, as Microsoft points out, those updates are dependent on your country, region, carrier and hardware capabilities. Windows Phone 7.8 was released after Windows Phone 8 as a way to give Windows Phone 7.5 users some of the features available through Windows Phone 8, which means that operating system has already been living on borrowed time.
Windows Phone 8 users who recently purchased their devices still have quite a while before their support dries up, so don't think you'll have to run out and pick up a new phone anytime soon. It's also an open question as to whether mobile users need active support for their operating systems long after launch. Google doesn't continue providing updates for Android 2.3 or Android 4 Ice Cream Sandwich, but there are plenty of devices on the market today that come preloaded with those OSes.