Auto HD/Automatic 4K for Youtube is a free Chrome extension that will automatically change the video quality of Youtube videos according to your selected preferences. All you have to do is to install the extension on your browser and run the program, and it will automatically remember your selected settings and apply them to all your Youtube videos. 

The extension was developed with the purpose of making Youtube video quality changes easier. So make sure to download and install this extension, so you can start enjoying streaming Youtube videos in HD quality.