This is what I do in my games:
Anything that uses charges is converted to a charges/day system. So, a ring of the ram is now kind of cool, since it has 6 charges per day. In my games, it went from being something that the party would sell ASAP, to a tool they actually use. (Expensive charged items blow, because every time you use them you're burning loot.)
For wands, I give them 10 charges per day for weaker ones, 5 charges per day for stronger ones.
Single use items remain the way they are.