I agree with what Eä said. It is quite the accomplishment to reach 10,000 posts, and I think that the ability to choose your own rank would result in some well-thought-out, indivdual ranks loved by their owners, and thus there would not be need for changing them too often. Besides the fact that we don't want to overwhelm the Mods, a Title should simply be pretty conrete, I think. Even names change all the time on here, and it would be nice if people could settle on one defining phrase for themselves.

So, changing every few months at the most is a good rule, I think.