Jack Shear put up a post about wands recently, reminding me of the old controversy. I have no opinion on that controversy. Broadly speaking, the division I use between wands and staves is that wands let you do one thing over and over again, whereas staves let you do many (or at least, several) things. Partially this is because wielding a wand is like wielding most weapons, in that it takes up one hand and binds the uses of that hand to it, while wielding a staff takes two hands and thus requires at least two options to replace the lost capabilities of that extra hand it requires.
I think I will therefore get rid of all wand types and replace them with one of these two house rules. I haven't playtested either, so I will have to try them out to see how they go.
A spellcaster who wields a wand may make a saving throw when casting a spell. If they pass, they retain the spell and may cast it again.
In systems that differentiate saves, the saving throw is vs. spells.
A spellcaster who wields a wand may roll a d10. If the result is higher than the spell level, they retain the spell and may cast it again.
If anyone has experience with either house rule, or similar rules, let me know.