This is a comment by writer Steve Moffat on how he views the process and nature of regeneration, which might be useful for writers.
Does each successive Doctor, as he regenerates, actually die?
For me (and this is in no way definitive, just my view, just an old fan talking) the answer is no. Regeneration is not death: it's way more frightening than that.
A while ago (don't worry, I'm not really digressing) I was talking to my little boy, as we cleaned our teeth. He was standing on a pile of books so he could see in the mirror and he looked at me, envying my height.
"One day we'll both be grown ups," he said.
"Well. One day, you'll be a young man and I'll be an old man, but yes."
"Why will you be old?"
"Time will pass, we'll get older. You'll get bigger, I'll get greyer."
He thought about this. "I don't want to get bigger."
"You'll be big and strong and you won't mind, I promise. You won't even remember saying that."
It was supposed to be comforting, but he just looked frightened, and thought for a moment. And he said, "If you promise not to get old, I'll promise to stay a little boy."
Moments like that stay with you - but little boys do not. He's fourteen now, a rugby player, looming over his mother and strong enough to lift me clean off the floor. And, no he doesn't remember a word of that conversation. So that little fella, cleaning his teeth on a stack of books, where did he go? Not dead, not at all, but gone from this world all the same. He's living the very future he was so frightened of, and he doesn't mind a bit.
That's what it's like for the Doctor, I think, and for every one of us: life goes on, but not this life. You haven't always been who you are now, and you won't always be. You're not one person, you're a whole committee standing behind one name. There's Toddler You, and Teenage You. There's Ambitious Young You getting very cross with Middle-aged You, who can't stop laughing. Passing judgement from the future, there's a Grumpy Old Git, or a Wise Old Sage, depending on how the wind blows. We are different people all through our lives - it's the price we pay. For the Doctor, that price is paid in one explosive moment, but it's the same thing really: the same fearful change. Physician, heal thyself! Regeneration, like so much that is so powerful in Doctor Who, is just our ordinary lives told as a fairy tale.