Just like Windows and Mac, Chromebooks have a lifetime of support and updates for the Chrome OS.  There are 2 ways to check your device or look at the lifetime of a Chrome OS device before purchasing.

To check a device by model

Go to – https://support.google.com/chrome/a/answer/6220366

Scroll down to the Chrome OS devices and expand to see the models from that manufacture, find the device you have or are looking at to determine it’s AUE – Auto Update Expiration date.

To check the actual device

1. Click the battery icon in the lower right
2. Click the gear icon Settings
3. Click About Chrome OS at the bottom, if you do not see that click Menu button and in the search type in About Chrome OS.
4. Under Additional Details, and under Update Schedule it should display either AUE – Auto Update Expiration date or This device will no longer receive software updates. You can continue using your computer but should consider upgrading.