Board Thread:Questions and Answers/@comment-220.245.79.209-20161019114754/@comment-30156797-20161024072306

yes, perks are "one time", at least when you start the fight. I am not sure about defending - if it's applied only the first time someone fights you or till you use the fighter next time.

But personally I don't use perks much, only a few times fighting much much stronger opponent as a psychological support