How long will a cell phone battery charge last

About 10% a month, so I will recharge it once in a while if you want to use it as a spare swap battery.

But lithium ion battery naturally degrade on the maximum charge they can hold, so even if you don't use it, it will still become unusable due to inability to hold a charge (dead battery). But don't worry about it too much because it looks as if you always use the battery and run out, that is why you want a swap battery right?

Thanks Pyree  

Thanks

Best answer selected by michaelkahler2000.