I strongly advocate getting a SIM for a negligible amount (less than 10 Euros) at a tobacco shop etc., sign up/register on line (there are often top up promos - one of mine on O2 has essentially been "free" for a year as the credit was more than I paid for the card) and use texting, callback, etc. and have free incoming calls...top up at ATMs. Traveling with a friend? Especially then - both get local SIMs and call each other "locally" as opposed to US phones with huge int'l roaming fees...keep numbers active with a text every six months (and even use cell carrier online services) - it isn't that big a deal, much easier internationally than in US, actually.

Do we have a SIM swap board here on FT? Maybe we should...