Tips in Italy are not mandatory, but it's customary to give them in proportion to the quality of the service received. It's not a fix percentage as it is in the US, but we could say it's proportional to how much the service fulfills or exceeds the expectations. So it's not given in case of a poor service, it's minimal in case of average and raises from there in a proportion the client decides. A tip is a gift and is up to the clients to judge its deserved it and in what measure. If asked, a waiter, porter, chamber maid, hotel concierge, driver guide or anybody else, will smile and say , whatever you think is appropiate. Everyone is happy to receive some extra money. In conclusion, everyone expect a tip but no-one will tell you how much it should be. But we are not going to leave you without an answer, here comes some help: 5 Euros a day for the chamber maid, in a restaurant they will be happy with 10%, as well as limos drivers.