Remember, most of your callers will obviously be 18 or older... BUT if he has a young voice, and you're not sure that he's of age, ask how old he is and what year he was born. Keep in mind that some callers who are well over 18 will call and give a fake age. He's not going to expect the YOB question, so he might get it wrong even though he's old enough to call! Go by his voice more than anything else - close your eyes and listen to him - if you just don't picture someone who is 18 or older having that voice, tell him that you're sorry - he sounds too young and you're going to have to disconnect. Then do so - don't wait for him to hang up. We want the call to show up as a VERY short one when the bill arrives!