The fact that wands come with variable starting charges in a nethack reference (among other roguelikes). If wizards are able to buy wands directly down the road there probably could be a "perfectly reliable" bit of code so they get their money's worth.

I actually have an idea for this but I'm going to save it for a later commit because it would turn this one into a [map] pull that is infinitely more likely to not be able to automerge