I don't feel like tracking charges...

I like the idea of players not knowing how many charges a limited-use item has, but I have better ways to spend my time than tracking every PC's items. In the past, I always just told them how many charges an item had an let them track it. This is lame, so I came up with this system...

Each wand/laser gun/whatever has a light on it when found. For a wand it could be a glowing crystal, for technology it could be a battery indicator LED or something like that.

Next, you just figure out an approximate number of charges you want the thing to have and use that to guide your decision as to what type of die to use to check if the thing was charges each time it is used. The super-simple method would just be that with a wand, every time you try to use it, you roll a die and if the result is a 1, the attempt fails, and the light extinguishes, indicating that the wand is out of charges.

A more complex method could be for a laser gun. Say it is found with a green glowing light, and you decide to use a d8 to check for charges. Just have the player write "green" next to the item. Whenever they try to use it, they roll a d8. On a result of 1, it works, but the light changes to yellow. Have the player change "green" to "yellow" next to the item on their sheet. On a result of 1 while the light is yellow, it works but the light changes to red. Again, have the player update their sheet. Then finally, if a 1 is rolled while the light is red, there isn't enough juice to get the shot off. That turn is wasted.

You could add even more fiddly bits to this if you'd like. For example, using an item when the light is red could trigger a % chance for overheating/backfire/explosion/timewarp. I like that sort of thing myself, so why not?