Why save them?

[Child of the 7th Age]

A few extra points, it is a while since I read the History of the Lord of the Rings volumes but I am fairly sure that Tolkien never intended to kill Frodo and Sam because I am sure CT quoted a note that JRRT had made saying if one of the hobbits died it should be the 'cowardly Pippin' ( I think this was before Faramir arrived in the story giving Pippin scope to redeem himself).

Mithalwen -

You're right. Frodo's fate was decided very early. I remember reading in HoMe that even as far back as "Bingo" Tolkien had notes in his papers that the chief character would return from the quest, live in a small dwelling on the outskirts of Hobbiton, and eventually decide to sail west across the sea.

The decision not to kill Frodo and Sam was integral to the plot and themes of the book. It wasn't something that he decided to do at the last moment because of feelings of regret.