Hello Robert,
As a courtesy I have attached the section on tipping from our Italy guidebook:
Tipping in Italy isn't as automatic and generous as it is in the US. For special service, tips are appreciated, but not expected. As in the US, the proper amount depends on your resources, tipping philosophy, and the circumstances, but some general guidelines apply.
Taxis: To tip the cabbie, round up. For a typical ride, round up your fare a bit (to pay a €4.50 fare, give €5). If the cabbie hauls your bags and zips you to the airport to help you catch your flight, you might want to toss in a little more. But if you feel like you’re being driven in circles or otherwise ripped off, skip the tip.
Services: In general, if someone in the service industry does a super job for you, a small tip (the equivalent of a euro or two) is appropriate...but not required. If you’re not sure whether (or how much) to tip for a service, ask your hotelier or the TI.
Happy Travels!