I'm replying to a previous theory submitted by nozz, and to wotmania's comments on it. nozz theorized that the Oath Rod has little or nothing to do with the Aes Sedai ageless look and long life, and wotmania disagreed, saying that the Oath Rod does have such a function, because the Kin, Windfinders, and Wise Ones don't have that same ageless Aes Sedai look. I would like to say that I don't think the Oath Rod has anything to do with ageless look thing. Remember that the seniormost among the Kin was over 600 years old, and while she didn't have the ageless look, she certainly didn't look old--Elayne and Nynaeve had the impression she had run away from the tower less than a century ago. Anyway, it's been demonstrated that the Kin, the Wise Ones, and the Windfinders do live very long lives because of their use of saidar, but only the Aes Sedai look ageless. I think that is because the Aes Sedai are the only ones who do a sort of formal training that takes years, with the novice gaining experience using saidar in many different ways. The Wise Ones and the Windfinders do train their novices, but not really in the same way--the Windfinders concentrate only on using the weather, and the Wise Ones have different focuses--some Wise Ones can't use saidar at all, and some, like Sorilea, have a very limited use of it. The Kin are afraid of being found out, so they try to use it as infrequently as possible. The Aes Sedai are the only ones who use saidar freely, all the time, and train specifically for its varied uses, and I believe that's where the ageless look comes from. I speculatethat Aviendha, for instance, might gain a touch of the ageless look from studying so much with Aes Sedai, even if she never touches the Oath Rod.
wotmania says: Well, I am going to stick to the idea that it is the Oath Rod which gives the Aes Sedai their ageless look. Here is something else I was thinking about this topic - I doubt anyone currently alive has used the Power as much as the Forsaken, and there is no sign of the ageless look among them. Now this could be because they are covering it up, but there has been no mention of any of the Forsaken constantly masking their appearance.
What about the novice or Accpeted (can't remember which) that Nyn mistook to be in 20 or 30 but is in actuallity 80 years old. She would have the same training as AS but neither Nyn or Eylane (Egw) made mention of a novice or Accepted with the ageless look. No AS gets the ageless look until she has sworn on the OathRod, regardless of how long that AS was a novice and Accepted.
And the aes sedai, that where seen in Rand's vision in the four book.
And moghedien saying that in the AOL, the block of Nynaeve would be solved in no time, and also said that in AOL they live much longer, something like they are young at the age of 300 dont remember exactly book or frase.
And our new friend from Seanchan more powerful than Nynaeve, and very joung indeed.
I do not believe it is the oathrod.
I think it is the three rings the novices have to go through to become accepted.
The only people who have the ageless look are Aes Sedai and Aiel Wise Ones. Only the Wise Ones that can channel get the agelessness.
Aes Sedai went through the rings in the White Tower to become accepted.
Wise Ones go through rings in Rhuidean to become Wise Ones.
Atha'an Miere Windfinders, The Kin, and Seanchan Damane do not go through any rings and do not get the ageless look.
Also as apk5 pointed out there was an accepted that did not look any older than 20 or 30 but is actually 80. As an accepted she has gone through the rings.
Why do cows moo?
Thats one 
All 
s must die
Something Already pointed out