You can drive until the bearings fail, but this risks causing other damage and making the repair more expensive. If you know the bearings are failing and you don't plan on getting rid of the car in the near future, you may as well bite the bullet and get the bearings replaced.
The 2004 Subaru Outback has all wheel drive.
The 2006 Subaru Outback has all wheel drive.
The 2014 Subaru Outback has all wheel drive.
The 2001 Subaru Outback has all wheel drive.
The 2009 Subaru Outback has all wheel drive.
The 2008 Subaru Outback has all wheel drive.
The 2002 Subaru Outback has all wheel drive.
The 2010 Subaru Outback has all wheel drive.
The 2011 Subaru Outback has all wheel drive.
The 2007 Subaru Outback has all wheel drive.
The 2013 Subaru Outback has all wheel drive.
The 2012 Subaru Outback has all wheel drive.