How long are servers considered "new" or "prefered"

[Zatofool]

I am leveling on a new server because of the incentives. Just wondering how long the "Road to 60" buff might be active so I know if I should hit 60 then level another. Thank you.

[MistakeNot]

I am leveling on a new server because of the incentives. Just wondering how long the "Road to 60" buff might be active so I know if I should hit 60 then level another. Thank you.

We don't know how long the servers will be considered new/preferred. If any of them should fill up to the extent it will be labeled "congested" it will no longer be considered new and bonus incentives will disappear.
At some point, when the populations have evened out, all the new/preferred/congested labels should be removed, but as to when that will happen - your guess is as good as mine.