Ever Vigilant

A useful card, especially with expensive allies like Beorn (Core), Faramir (Core) or Gandalf (Core).

like sirprim said, or use it also with smaller characters that have an important action that requires them to exhaust like Gleowine (Core), Daughter of the Nimrodel (Core), since it may become a dead card in your hand if you just wait to use it on the big chars that you are waiting to draw and then it may be too late.

This is a great card, although, the Leadership sphere have so much great stuff it may be hard to find a place for it.

(Addressing Reager's comments) I'm no expert, but I've found it's usually better to use cards when you have a fairly good opportunity (not necessarily the FIRST opportunity) to do so rather than try to save them for some big play that may or may not come later in the game. The earlier you can establish any advantage the better.