Grimm has been sitting on my shelf for awhile now, but I have been able to finally convince/coerce some of my friends to play it. While going through character creation with them one of them asked about expending traits. I told him you expend traits to activate certain abilities from iconic traits, talents, or abilities. Then he asked me how you regain expended traits. And I was stumped. I was able to find one of the talents which allows a player to regain a point of an iconic trait but nothing else. A lot of talents and abilties allow the multiple expenditures of traits but it seems to be at the cost of a permanent drop in that trait. The book mentions tracking the drops separately and the character sheet has two spaces for grade and max grade. So either the traits refresh after so many scenes or the completion of the story. Or the traits must be bought back up. A permanent drop is also compounded by the fact the drop could make the character's traits drop below the required level for talents and moving along the talent progression becomes harder. It is more than possible I keep missing the ruling on this in the book, I've done it before. I am in favor of making all expended traits refresh at the end of the story, since Grimm is weighted enough against the players already.
So I am asking can somebody point out the ruling for regaining expending traits in the book? And if there is no ruling what are people's thoughts on a fair method of regaining traits?