See the Article Herehttp://chromeunboxed.com/why-googles-end-of-life-policy-for-chromebooks-isnt-a-big-deal/
However, we will soon be facing the end of life on our initially purchased Chromebooks and we will have to start replacing some of these devices as they start to fail (having lived a full 5 years). This will start in late 2017 /early 2018.
Google officially supports the OS (operating system) on a Chromebook for 5 years. After that point, the device will no longer update. However, many apps support older versions of Google's Chrome Browser. After that, the device is most likely going to be decommissioned due to age or damage.