when should a 2011 Subaru Outback have struts and sway bar replaced

Replace struts when the ride is mushy or bouncy. Replace the sway bar when it breaks.

Ha! I WISH the rear bar would break, as that would be a fine opportunity to install the fatter STi version to improve handling. Struts on this 2010-2014 iteration are pretty solid, and only require replacement if "broken" by an egregious pothole. The swaybar ENDLINKS can rust off the swaybars, however...that's what my friend above is referring to. They're easily replaced. Note that the struts therefore do NOT "wear"(they're gas- charged) so replace only a single broken one if you pop it. If the ride is "bouncy" drive over potholes on both sides individually to determine L from R, or stand on the bumper and bounce up and down; usually driving is the better differentiator. Again, replacing the REAR anti-swaybar with the 20mm STi one is an extraordinary value, and will actually "brace" your rear struts a bit too. But maybe you'll want to wait until you need an endlink or strut...but that may be years. Depends upon potholes and salt. Best. Ern TSG/B