My first conversation with DD on this issue was about how I'm going to turn into a pile of ash and bones upon my death. I can't recall her exact age but I believe she was around 3 and a half?

I was not prepared to discuss it.

Now that she's 4, she seems to have gotten very pragmatic about it. She is planning on learning to drive as soon as possible so she can get to places after my death. She has accepted that everyone dies and as she puts it, there is nothing you can do to stop time. She doesn't seem to be all that traumatized by understanding mortality at a young age.

As for arguing and debating endlessly, we tell her that we're reasonable and we're always open to listening to her opinions as long as she is being rational. That doesn't mean that she'll get her way but if she makes a convincing and persuasive argument, then we might change our mind. She's gotten better about dropping things when she has no valid counterpoints.