you have reached an answering service that isn’t in Houston? They’ll ask you for your phone number, area code first.
In Houston, there are no numbers that don’t have area codes. We have at least three: 832, 281, 713. And everyone has to dial the whole area code.
Compare this to my friends in New York who have lived there for forty years and whose phone number, in total, only has five digits.
I am sure that soon/eventually all of the US will have 10 digit phone numbers and that then we’ll have to add more numbers to the system.