Why doesn't Y.A. let you edit your posts or post twice in the same thread?

Questions can't be changed. They can be added to. See the EDIT menu.

Answers can be changed up to the time the vote starts or a best answer is picked.

People give answers based on what the question says. If you were allowed to completely change the question it would make the answers wrong. Additional information should never change the question, only add to it.

₪ ʎəɿʞɹɐq ₪

You can add details to your question by clicking the Pencil/Edit then add details. No limit, same as using the edit for your answer.

Let's see.

This is my first edit.

And this is my second.

And here is my third. I think there's something you have missed - it certainly works for me.