Hmmm... I would have to say
need sounds right. They need not count the years because they are immortal. They live forever, and can only die from wounds in battle or a broken heart. Time really has no effect on them. That is it does, but it takes so long that it wouldn`t be noticable to a mortal, or perhaps one of there own. Counting the years would be a waste of time. Darn. Now that I think about it, counting the years wouldn`t be a waste of their time, seeing how they have so much of it. I guess what I`m trying to say is, why count the years if you are going to be around forever?
This brings up another idea. Do you suppose most elves knew their own age? I guess if they knew the year as it was to the race of Men (I can`t really decide how to word it), when they were born, they could always figure it out. My mind is slow today. Any ideas?

Nimrodel