Google justupdated its privacy toolsacross a variety of services including Search, YouTube, and Maps.
Now auto-delete is the default for all core Google activity controls.
YouTube will be set to 36 months by default.

If you want to keep your history intact, you’ll need to do that manually.
You’ll no longer need to install an extension for this important service.
Bottom line: Your data is important, and should be kept secure.
These tools are just another way to help make that happen, but you have to use them.