Animated Shield duration?

[Marauder]

I was curious as to how long a shield that has the 'Animated' special ability defends the user subsequent to activation. From the SRD:

"Upon command, an animated shield floats within 2 feet of the wielder, protecting her as if she were using it herself but freeing up both her hands. Only one shield can protect a character at a time."

From this I can assume that the power can be activated any number of times per day (as a standard action), but for how long? I am inclined to use the caster level in the Special Ability description and refer to the 'Animate Objects' spell [caster level 12th, therefore animated shield duration: 12 rounds].

Thoughts or alternative viewpoints greatly appreciated - thanks!

 

[Jeremy]

My initial guess would be indefinately, or rather, until it is inconvenient to have an orbiting shield (i.e. combat is over, or you've got a hand available again).

 

[laiyna]

Indefently or until the person who got the shield floafting around him/her is slain. But it makes some tasks very hard to do when you got a large shield floafting around you. (like sleeping, memorising spells, etc)

Lai