I am traveling to Italy next month and part of my trip is to Florence. I would like to rent a car for the day to see the countryside in Tuscany. Some sites I've read say I have to have an international driver's license while others say I do not. I checked and it appears I can easily rent a car from Avis in Florence but I do not see any guidance as to driver's license requirements. Obviously, I am a licensed driver in the US. Can someone tell me what the requirements are based on experience or refer me to a reliable source for this information?
Whatever the requirement is from the car rental, you are required getting an international driver's license in any case by Italian law, unless you have a EU driver's license. The international driver's license is simply an official translation of your driver's license into many languages, which costs 15 USD and should take one day if you go to get one in person instead of trying to get one by mail.
An IDL is required, which you can obtain from AAA.
The rental agency usually does not request it. However, if you are pulled over, you will be ticketed and in some areas will be "required" to pay it immediately.
As for driving in Florence, I would not recommend it. The public transportation is excellent. Florence, just like most towns in Tuscany and throughout Italy, has restricted driving zones. Some zones require permits and others do not allow any cars. Several of those areas are monitored via cameras. You will get a ticket sent to the rental agency which will then forward it to you. They can range anywhere from $50 to $500 to more!
My first few trips I rented a car, but now I just rely on public transport. Or I will hire a driver to tour smaller towns.