Having played Dungeon World a handful of times, I love it. I still find the concept of accruing and spending hold a bit confusing. I purchased the pdf version of the game. I found the following text in an online version:
…Give you “hold.” Hold is currency that allows you to make some choices later on by spending the hold as the move describes. Hold is always saved up for the move that generated it; you can’t spend your hold from defend on trap expert or vice versa, for example
So a fighter accrues 2hold defending the wizard. In what context could he then spend that hold? And how long can he save that hold before spending it?