- being on fire
- blasted by an area effect spell
- falling more than ten feet
- walking through waist high water
- getting critically hit
then the wizard must make a save vs breath weapon (or reflex save, or whatever) or lose one component. Glass breaks, the component is squished when the wizard sits on it, or the magic crystal falls out of a pouch and is lost in the mud. Randomly select on spell that the magic-user has memorized, and cross it off as though it had been cast.