Are there "end of life" plans for Android?
For android devices the answer is: 18 months is the maximum supported lifetime.

I found this in the Google Android FAQ. It is said that the 2 year old Galaxy Nexus does not recieve an Update to Android 4.4 "KitKat":


  Galaxy Nexus, which first launched two years ago, falls outside of the 18-month update window when Google and others traditionally update devices.