I am very proud of self, because I managed to do a nearly five-week trip in France and Italy with only a carry-on bag! It is what Rick Steves recommends, and he is right. It isn’t easy, of course, but once you’ve done it you realize it is the only way to travel.
That said, were I to return to Italy to study for a semester (a possibility in future) I would not be able to manage that. A carry-on bag for three months? I don’t think so. One would end up buying too much and then have to buy a bigger bag with which to return home.
Still, it is terrific to not have to wait at the luggage carousel, and not have to fear losing one’s luggage. Better Half had his bag lost on the trip back, though he did — thank goodness — get it returned six days later. I’ve had my luggage lost twice: once coming back to Canada from Turkey, once coming back from Israel. Both times I got the luggage back, but it taught me to pack light.