I find myself in a weird position when it comes to my craft name.
I am naimh here, there and well just about everywhere. I have friends who I met using my birth name, who have overtime even started to call me naimh, I answer to it as readily now as I do my birthname. So for all intents and purposes you could call it my public craft name.
I do have another name, which is used during magical working, it is known to my mentor and a small group of trusted people. But even that is not the full name that was given to me, only me, my mentor and my closest friend (who happens to also be training with the same person and as a result of participating in a joint working became aware of it), know the complete name. I suspect it will stay that way.
I cannot imagine changing my name at any point in the future, my private name bears some level of responsibility within the arena in which I am being trained, and I had to prove myself to recieve it; so it is a name very very dear to me. I suppose it is possible at some point in the future I will have to undergo another period of "proving" and recieve another name, stranger things have happened, but at the minute I am not sure I could even imagine recieving another one.