My F1 Visa expires this December 7th. I want to take a semester break due to personal reason. My school starts January 16. I have heard about 30 days rule that you cannot enter USA before 30 days before the classes start. So that means I won't be able to enter USA before December 7th. Then I will have to apply for a new student visa. Does 30 days rule apply for semester break as well? Has any of you tried to enter USA before 30 days? If 30 days rule indeed applies to my case, how diffifult is it to get a new student visa? I appreciate anyone's help.

Ask your international advior, only he/she can give your the correct answer. Getting new student visa is not an good idea. They usually deny to provide new student visa. 

 my school was to start on Jan 16th I came back on November 26th after a semester break. So there is no 30 day rule, I guess. but still ask your advisor. You should not be out of US for 120 days or your I-20 will automatically be revoked. make sure you are in Nepal less than 120 days or 4 months.

 It is not 120 days, it is 150 days. i stayed in nepal for 135 days during my semester break and came back.

 And it is not i-20 , visa itself will be invalid.