[Morwen]

Well, even this could be questioned, I believe, when it comes to Middle-Earth. After all, Sauron WAS defeated with the broken sword.

Sauron's "defeat" by the broken sword is an exceptional circumstance. If you're in the middle of a battle and a broken sword is what you have to hand then you use it. If one has any choice in the matter then a whole sword is preferable. If that were not true in Middle Earth then I can't imagine why the Elves bothered to reforge the sword that was broken.

And then, the other thing is - how many enemies armed with an actual weapon, the more a weapon like a sword, Aragorn met in the Wilderness? Not speaking about Gondor and Rohan, I would side with Lommy there and think that he probably used a different sword there, also for the reason that he should not reveal tokens of his heritage in these places yet. He probably was given something by the king/Steward, first he probably got some "basic weapon" like every warrior, later, he may have been personally given something better for his bravery and good service. Anyway, back to what I said, in the Wilderness his main enemies were probably wild animals and from time to time, on longer journeys, it might have been an Orc (probably badly armed), rarely a troll or something like that (who likely did not use any weapon). Let me also point out that I don't think the rangers actually fight that much: or, of course they do, but their main purpose is "protective", the mere presence of them has some effect. They monitor the area and therefore the enemies don't even come there. And only when, let's say, a band of goblins gets too close to human settlements, a larger group of Rangers appears and drives them off.

Apart from Gondor and Rohan, Aragorn's wanderings were not limited to the wilderness. He spent time in the East and deep South "exploring the hearts of Men, both evil and good, and uncovering the plots and devices of the servants of Sauron" (LotR, Appendix A) These sound like tasks where a whole sword might come in handy.

As for his wilderness tasks, my take on these is precisely why I don't see Aragorn carrying Narsil along as matter of course on every journey he ever made. His tasks would have likely been arduous, involving long journeys where he would need to travel fast and therefore want to travel light. I can't see him taking something along that would not be of any use and might perhaps be a hindrance.

The idea that he needs to sit and look at the shards from time to time to remind him of who is doesn't strike me as something Book Aragorn would need. Movie Aragorn maybe. But I don't think that Book Aragorn needed that kind of constant reminder of his purpose. Nor do I think that it lessens the significance of an object if the owner doesn't carry it with him everywhere. I strikes me that this depiction of Aragorn's behaviour is Gollum like, or Ringbearer like perhaps, this idea that you need to have an object constantly near you and be reassured or fortified by its presence.

Of course, then he'll be really happy, as he spent lots of time trying to find out whether any heirs still exist. But here we must once again grasp the logic of the tale. It simply could not have happened. Or, if even that happened and he were slain and the shards taken, there would have needed to be some other heir elsewhere, and the shards will be re-gained (very probably, the Orcs who would slay him will not even have the chance to return to... wherever they'd come from, or let's say, had that happened for example in Moria, then some Fellowship who will travel this way a long time after that, will find a strange skeleton with broken sword - the Orcs of course ignored some useless broken sword and took only what seemed valuable - and suddenly one of them, young Arasomething, would suddenly yell "Oh, it must be my relative"...).

... or the author could avoid all of that and simply have him leave Narsil at home.