2) AGADAH: LEARNING TORAH FOR TWELVE YEARS
The Gemara records stories about Tana'im and Amora'im who left their homes to learn Torah for twelve years after their marriage. What is unique about twelve years that they all chose to go away to learn for specifically that amount of time?

(a) The MAHARSHA explains that the Mishnah in Avos (5:21) states that a person is enjoined to get married at the age of eighteen, and the peak of his strength is at age thirty. Since a person learns best after he is married (Yevamos 62b), the best time to set aside for learning Torah are those years between eighteen and thirty.

(b) The CHIDA (in Sefer Mar'is ha'Ayin) writes that there are (approximately) 613 weeks in twelve years. By going away for twelve years, one can spend one week learning each Mitzvah.

(c) The BEN YEHOYADA adds that the twelve years of learning are comprised of six years learning the six Sedarim of Mishnah and Gemara with breadth (b'Ki'us), and then six years of delving deeply into the six Sedarim (b'Iyun).

He points out that there is an allusion in a verse that success in learning comes after a person has learned for twelve years. The verse states, "For six years you shall sow your field, and for six years you shall harvest your vineyard, and you will gather the produce" (Vayikra 25:3). "For six years you shall sow your field" -- just like sowing a field prepares the way for growing fruits, one must spend six years preparing the way for gaining understanding in the Torah by learning a large breadth of the Torah. "And for six years you shall harvest your vineyard" -- these are the six years of delving in depth and coming to Halachic conclusions in one's learning. After that, then "you will gather the produce." "The produce" refers to the Torah (Bava Basra 145b), for after twelve years of learning one will have made a true acquisition in his learning of Torah.