The calling plans and contracts are so long and difficult to understand, you have to be an accountant or lawyer to understnd them.
Many carriers claim to have calling plans to give you unlimited night and weekend minutes. But if you make a call or receive a call from certain geographical locations, your phone might route your calls through another carriers' network. And you get charged long distance and roaming.
How to avoid those long distance and roaming charges? Do some phones automatically route your calls throught another network, without you allowing it to? Is there a way to know, that your call will be routed through another carrier, before you dial the call?
Is there any way to know you have used up your free minutes?