Question: How frequently can I change server?
Answer: You can change server not more frequently than 3 times in a month!
In the billing (menu Servers), there is a note right above the table
WARNING! You can change server not more frequently than 3 times in a month! You have not changed server this month.
Later, when you changed the server, you will see the following note:
(http://s017.radikal.ru/i432/1111/7c/6acb4cbc0eec.jpg)