– Q. Someone that requires a very delicate brain operation, if he can wait should he do so until the ‘Good Mazal” month of Adar, or do it after Tu Bishvat?
A. On a similar question (4107) we wrote:

“On question 1634 we mentioned that Adar is a time when good mazal prevails, so it is a propitious period to begin new shiurim, establish new mitzva projects, and other endeavors whose success will bring joy. (See question 990 regarding new business ventures).

Indeed, on the first day of Rosh Chodesh Adar the date written on a Halacha official document such as a Get, would be; ‘The thirtieth day of the month of Shvat, which corresponds to Rosh Chodesh Adar.’ Nevertheless, Horav Shlomo Miller’s Shlit’a opinion is that it is already included on the auspicious and fortunate good mazal of Chodesh Adar.

On question 990 we added: “Derech Sicha, (Miketz p. 188,) Nitei Gavriel, (Purim – Teshuvos 2) et. al., opine that it begins from the first Adar. Nitei Gavriel (ibid. 464) quoting the Munkatcher Rebbe, adds even from Tu Bishvat.

The reason why the beginning date and time is so undefined and not exactly and clearly established, may be that likely it depends on the nature of each individual and his particular needs and situation. The great month of Adar is willing to acc ommodate itself to the needs of each individual.”

Rabbi A. Bartfeld as revised by, Horav Dovid Pam, Horav Aharon Miller, Horav Chanoch Ehrentreu and Horav Kalman Ochs Shlit’a