Arizona is a one-party state, which means only one person in a conversation is required to know the it is being recorded.
I live in Texas, which is also a one-party state. Anyone can buy an app that records all your calls, and you can save them to your computer or phone. You can also list phone numbers of people for which you do not record. The app is inexpensive, and it has come in handy on more than a few occasions.
Nice tip...thanks