currently have a 2014 Vizio P series, so I am already behind with that. I would like to be current for hopefully 3 years before Im outdated. One of the sets Im looking at is the Sony 900f and thats already 2 years old.How often do you buy new sources? The reason I've had to update in the past was to have the TV compatible with sources and the receiver/processor. A lot has changed over the past few years and with streaming becoming the main source for media, more changes will come. Not all will require a version change, but major changes like adding ARC and ethernet require hardware changes. Without the correct version of of HDMI your TV or player apps may not work.