I don't know, but i have been using a single clickbank account since is registered there. Is there any advantage to change your clickbank account regularly? I mean, can your commissions be affected due to your account longevity?
I don't think there is any advantage to change your clickbank account. BTW, U can have as many CB ac as U like.
From a vendor's point of view, it's good to help separate the brands of your products. From an affiliate's point there's not much benefit. Some people have reported that sales pick up if they create a new account, but that's pretty unsubstantiated at this point. Clickbank's commissions are fixed, not like many CPA networks where they are negotiable.
I know some affiliates create different account so that it is harder for competitors to track their aff ID and reverse engineer their tactics. But I personally only have one clickbank account (for now).