Question: We learned above that it is most important to wear the tefillin during the Shema section and the Shemoneh Esrei. Suppose a person is able to wear them throughout most of the service, but for one reason or another, he must take them off a bit early - e.g. he must leave a few minutes early from the minyan and does not have enough time to complete the davening on his own before removing his tefillin. Is there a point which is more preferable than another to remove the tefillin?
Answer: Obviously, the longer he is able to leave them on, the better. The halacha gives us a hierarchy of junctures (some of them based upon Kabbalistic sources): 1) Leave them on through the recitation of ‘four Kaddish-im (Kaddish-es)’. For the standard Ashkenazic service, this means: a) the half-Kaddish before Borchu (Artscroll Siddur, p.82), b) the half-Kaddish after the Shemoneh Esrei (p. 138), c) the Full-Kaddish after ‘u’Va l’Tzion’ (p. 156) and d) the Mourner’s Kaddish after ‘Aleinu’ (p. 160). (If you cannot wait that long…)
2) Leave them on through the third Kaddish (i.e. Full). (If you still cannot wait that long…) 3) Leave them on through the major part of ‘u’Va l’Tzion’, particularly the ‘kedusha d’sidrah’ (see commentary on p. 153), removing them before the last paragraph beginning with the words ‘Yehi ratzon mil-fanecha….’ (“May it be Your Will, etc.”) (Note: The Mishnah Berura writes that it is improper to be taking off and wrapping up the tefillin while ‘amein, ye-hei sh’mei rabbah mevorach’ is being recited by the chazzan and congregation. He writes that it would be like trying to do that while he was making a bracha - which is improper as well.)
Question: When should the tefillin be removed on Rosh Chodesh? On Chol Hamoed?
Answer: On Rosh Chodesh, the tefillin are left on for Hallel and Torah reading and removed before Musaf. On Chol Hamoed (i.e. for those who wear tefillin then), they should be removed before Hallel. (Note: A discussion about wearing tefillin on Chol Hamoed in general will be forthcoming, iy”H.)