Many (if not all) merchants in international airports accept multiple currencies, with the cash registers doing all the conversions automatically (at rates favorable to the merchant, not the traveler, of course). So you can use dollars in FCO, but it makes no sense in your case because you will need Euros anyway. It is handy for someone changing planes in Europe en route from the US to Asia, for example, not to have to get euro cash s/he could not use on the rest of the trip.

First with a couple of huors layover you may or may not hve time to eat anything - depending on which gates you land/depart from, security lines and everything else.

If you do have time to eat you just use your credit card to pay (but NOT Discover, which is not supported in europe).

You never change any money at all. Just pay for everything you can with your credit card and use your debit card to pull euros from you cheking account at the nearest ATM for walking around money.

Just a quick thank you....your help has been very much appreciated!

Leslie