Global vs. Individual listeners on multiple instances

Scenario: Up to 50 instances of a display object are arbitrarily positioned on the stage.

Is it better to create listeners for each individual instance or create one single global listener and then somehow find out which instance triggered the listener? If the latter is preferred, how would you suggest I go about doing that? Will event.currentTarget tell which instance it was? And should I register the listener to the stage?

Thanks.