When is Atah Chonantonu said on Sunday morning?

A person who did not daven Ma’ariv on Motzei Shabbos must daven two tefillos on Sunday morning. If he already said Havdalah, he does not say Atah Chonantonu during either Shemoneh Esrei. If he did not make Havdalah, the Achronim disagree on the proper way to daven. One opinion holds that Atah Chonantonu is not added to either Shemoneh Esrei. Since he must still say Havdalah, there is no make-up for Atah Chonantonu. Others say that Atah Chonantonu should be added during the second tefilla, which is the make-up for Ma’ariv. A third opinion holds that it should be added to the first tefilla, since it is the first tefilla that he is davening after Shabbos.

סי' ק"ח ס"ק ל"ג ביאורים ומוספים דרשו 67

Is there tashlumin on the night of Shemini Atzeres if one missed Ya'aleh V'yavo during Mincha?

If a person omitted a crucial addition to Shemoneh Esrei and only realized it at the time for the next tefilla, the obligation of tashlumin hinges on whether the addition that was omitted will be recited during the upcoming Shemoneh Esrei. For example, if a person neglected to say Mashiv Haruach during Mincha and only realized it at night, he should recite tashlumin during Ma’ariv since Mashiv Haruach is still added at that time. In a situation where the omission is not repeated during the upcoming Shemoneh Esrei (e.g. one who misses Ya’aleh V’yavo at Mincha and that night is no longer Rosh Chodesh), there is disagreement about whether tashlumin should be recited. One should daven a second Shemoneh Esrei, stipulating that it may be a tefillas nedavah. When Rosh Chodesh occurs on Friday and does not continue into Shabbos, if one omits Ya’aleh V’yavo at Minchah he will not be able to daven a second tefilla during Ma’ariv. Since it may only be done as a possible nedavah, it is not an option on Shabbos, when nedavos are not accepted. A similar halacha applies if one forgot Ya’aleh V’yavo on Hoshanah Rabba at Mincha. He will not be able to daven two tefillos during Ma’ariv, since that tefilla will only be mentioning Shemini Atzeres and not Sukkos. Also, nedavos are not accepted on Yom Tov.

ס"י ס"ק ל"ה-ל"ו ביאורים ומוספים דרשו 72

Is it necessary to repeat the brocha if one began Ya'aleh V'yavo on a typical day?

In the opinion of many Achronim, making an inappropriate addition to Shemoneh Esrei is similar to talking and necessitates returning to the beginning of the brocha. B’dieved, though, if the brocha was completed and one continued further in Shemoneh Esrei, he does not have to go back. A mistaken addition would only be an issue if it was completely incompatible with the present day. However, an addition which can technically apply on any day would not invalidate the brocha. For example, if a person started saying Ya’aleh V’yavo on a typical day but did not reach the point where he mentions the special day, he should stop saying Ya’aleh V’yavo and continue onward with the brocha. This is because the first part of Ya’aleh V’yavo contains general words of tefilah that could apply on any day. If one added Al Hanisim on a day other than Chanukah and Purim, he must repeat the brocha. If he added it on Erev Chanukah during Minchah, however, or on the last day of Chanukah during a Mincha that continued after sunset, it is not necessary to repeat the brocha.

סי"ב ס"ק ל"ז-ל"ח ביאורים ומוספים דרשו 77

• If a person missed Ma’ariv on Rosh Chodesh and will be davening a make-up tefilla at Shacharis, he should--l’chatchila--include Ya’aleh V’yavo in both tefillos. If, however, he omitted it during the second tefilla, he has still fulfilled his obligations. Since the second tefilla is the make-up for Ma’ariv, the Ya’aleh V’yavo requirement cannot be more stringent than it is for Ma’ariv itself.

• If one missed Mincha on Shabbos, he must daven two weekday tefillos during Ma’ariv. The proper method is to include Atah Chonantonu during the first tefilla and omit it during the second one. This shows that the first tefilla is for the primary obligation and the second one is the make-up. If he omitted it during both tefillos, he is still yotzei both obligations. If, after omitting it during both tefillos, he ate before making Havdalah, it is only necessary to repeat Shemoneh Esrei for the present obligation but not for the tashlumin.

• If one mistakenly recited the weekday text during Mincha and only realized the error after Shabbos was already over, the Rishonim disagree about whether he is obligated in tashlumin during Ma’ariv. The disagreement centers on the following question: When a person omits a timely addition to Shemoneh Esrei (such as the Shabbos nusach) and must repeat it, is the repetition because his Shemoneh Esrei was entirely invalid, or was his tefilla valid but it just required repetition with the proper addition? If it is for the latter reason and his Shemoneh Esrei had a certain level of validity, it would be pointless to repeat it at a time (Motzei Shabbos) when he will not be adding the part that was omitted. 

• When is it necessary to delay the start of Shemoneh Esrei?

• Does a person who davens a lengthy Shemoneh Esrei have to wait to begin until he hears Kedusha?

• Is it necessary to travel to respond to devarim shebekedusha?