Carrying our passports in Italy?

Technically, you are supposed to have your passport on your person. (Don't ask me if I do that.)
Some carry a photocopy while leaving the passport in hotel safe.

Italian law requires that you carry your passport at all times.

Your DL is not valid as ID in Italy; however, it can be handy if you are renting an audioguide.

A US Drivers License means nothing to a foreign government or vendor. The Italian law is that you have a passport with you at all times. I guess it's your decision and how risk adverse you are. Safe travels!

There have been many discussions on this topic
A search will bring them up

In short
It is required by law to have your passport with you
Your passport is the most important thing you travel with, along with a credit card it’s your ticket home or to a safe place should the need ever arise

Carry it deep in a money belt on your person

Yes we have been stopped randomly and asked to show our passports-actually twice on the same trip
We observed police checking passports at another location

We were stopped once in Sicily for a DL check and I showed my IDP and then they ask for my PP; they spoke no English and was glad I had both.

If you choose not to carry your passport, then at least carry a copy of the photo page and driver's license.

https://www.gov.uk/foreign-travel-advice/italy/safety-and-security

You must always be able to show some form of ID. In most cases a copy of the photo page of your passport should be enough, but you may also be asked for a second form of photo ID. The police will normally ask for your full passport if you are stopped while driving.

There seems to be more unease in the world lately, so even though I used to keep my passport when wandering around town in the hotel safe, I'm more inclined now to carry it on me in a money belt.

Our tour guide in Italy (who was from Rome) said to take a picture of our passport for when we had to show it at a place or two. And I did that, just so I didn't have to pull it out. But I kept it in my money belt the whole time on me. It is handy having a photo of it so you don't need to pull it out here and there.
Edit: as already said, nobody cares about your USA driver's license. Honestly, I should have left mine at home. I used my passport at the airport. Even for the domestic first leg of the flight, they wanted my passport since it would be needed at my next leg. And then a few times, including while purchasing something that would be connected for a VAT refund, and one or two places we went to (I don't remember which, maybe the Vatican and the Pantheon??) they wanted to see a photocopy or photo of our passport.

Edit: as already said, nobody cares about your USA driver's license. Honestly, I should have left mine at home.

Unless you plan to drive, then you need your US license and an IDP.

If you drive a car you need your US Driver's License, your International Driver's Permit issued by the AAA, and your passport. If you drive the likelihood of being stopped and checked by the Police or the Carabinieri is high, even if you don't do anything wrong. They routinely stopped motorists just to check their papers (drivers' licenses, insurance, car documents like registration and attestation the car passed the bi-annual mechanical check, which is an all comprehensive check, not just smog), they also check your criminal record online.

If you take a day trip out of town, even by train, take your passport with you.

If you are just walking around town, you can take the risk of leaving your passport in the hotel safe, but carry another form of ID and a photocopy of your passport. In the unlikely event your are asked to show papers by the Police or Carabinieri, just show the above, and say you left the actual passport to the hotel because you were told there are a lot of pickpockets in Italy.

Do what ever you want. Just be aware that being on the street without your passport is against Italian law.

With the advent of nominative tickets for timed entry to popular tourist sites, your passport is usually required as identification to prove that you are the person whose name is on the ticket.

There are risks with whatever choice you make.

If you leave it in the hotel safe, it will be safe from thieves or loss, but you might need it to prove who you are at a museum if you have a ticket with timed entry and the museum staff decides not to accept another form of ID but a passport with at least 6 months of validity. Or you might be stopped by a policeman because you look suspicious or an illegal migrant, and the policeman may not believe you are an American tourist based on your passport photocopy and your US issued driver's license.

If you carry it around you won't have to worry about not being able to show a policeman you are not an illegal alien, but a US citizen, or you can safely enter a museum with timed entry without worry. But if you lose it or someone steals it, you need to go to the closest US consulate, which in Italy are only in Rome, Milan, Florence, and Naples. Then you must prove you are an American citizen by providing the consular staff a photocopy of the lost passport or your birth certificate, and, if it is not a weekend or holiday in Italy and in America (Consulates observe holidays of both countries, for good measure), after paying fees you should receive an emergency passport generally on the same day. Of course it is possible that while on your way to the Consulate in Florence, Rome, Milan or Naples, you might be stopped by an Italian policeman, who might ask you for your passport, in which case you'll have to explain it was lost/stolen and you are headed to one of the 4 aforementioned cities to get a new one.

Moral of the story. When you carry your passport with you, make sure it is kept very safely on (or inside) your body, because losing one (or having it stolen) is a big mess that will make your day (and your vacation) miserable.

I carry an officially issued US passport card separately from my US passport when traveling internationally and while the passport card is not accepted as a passport except in a few countries like Mexico, Canada, Bermuda, etc., my thinking is that it would help with identification and would be better identification at a US Consulate if my passport were lost or stolen. I would rather have the card to use on my way to a US Consulate when stopped by the authorities than a photo of my passport which I also bring along. That said, I do keep my passport on my person when traveling.

I would highly recommend keeping your Passport with you at all times when travelling in Europe. If you don't expect to use it for hotel registration or whatever, keep it inside a zip-lok bag in your Money Belt (the zip-lok prevents moisture from damaging the Passport..... if it's damaged, it can be refused and will have to be replaced).

I learned the value of keeping my Passport with me on my last trip to Italy, when I was injured. That was the first thing the hospital asked for when I arrived there. I couldn't return to my hotel to retrieve it, and went straight from the hospital to the airport. I was travelling solo, and the situation would be different for those travelling with someone else.

Italian law requires that you carry your passport at all times. Failure to do so can result in fines and a little jail time.

Now we can rationalize why we dont need to obey the law when we are a guest in a country.