There is an interesting argument on that subject at the Tolkien Virgin site. After each of the Virgin essays is a section of comments by readers (for those who haven't found it, scroll down.) And the final essay has this discussion about Aragorn's death. ;)
"Aragorn's whole life is overshadowed by the fear of repeating his ancestors mistakes, Isuldur's failure to destoy the ring, Numenor's destruction, etc...."
"..His choice to die gracefully rather than to cling to life until he is feeble and dotard is tied to this in that, Death was a gift to men from Illuvatar. Then Sauron fooled men into thinking it was a curse and should be feared and they should crave immortality. Which was the main reason Numenor was destroyed."
"So, in a way, this is his last test, to die peacably and willingly without fear when it is his time go(lest he start Gondor on Numenor's path). ""
I've been kinda mulling this subject around in my head for a while. Tolkien was curiously a Roman Catholic who would have approved of assisted suicide? You think?
Or was he suggesting only that old kings should turn their kingdoms to younger men before they are senile old fools?
From another post there --
"And Atanamir lived to a great age, clinging to his life beyond the end of all joy; and he was the first of the Numenoreans to do this, refusing to depart until he was witless and unmanned, and denying to his son the kingship at the height of his days. For the Lords of Numenor had been wont to wed late in their long lives and to depart and leave the mastery to their sons when these were come to full stature of body and mind (Akallabeth, top p.266 in my hardcover edition)"
I'm curious where Tolkien was going here, with this?