The Painkiller Saga
So I love me some wands. I also love me some magical fuckery. So wands no longer have charges, they overload and maybe explode instead.
Wands or staves are overloaded when spell level x uses in the last day / 5 is greater than one. Something appropriate for the spell school happens when you use an overloaded wand. Could be good or bad. A wand that has an evocation spell in it might be subject to a heat metal spell when it is used overloaded. The strength of the effect scales with caster level of the wand.
Additionally, there is a chance of overload failure when you use an overloaded wand. (caster level x spell level x uses in the last day / 100 percent, round up for percentile die) Overload failure is generally a bad thing. It destroys the wand in an explosion of magical energy, again related to the school. It will be hilarious.
I have it scaled out for a bit of balance and mostly no change in real play. An average 3rd level wand will overload after two uses and has a 2% chance of failure after ten uses. A 5th level spell from a staff will overload after one use and has a 5% chance after ten uses. Even with spamming, having your fancy staff explode won’t necessarily happen.