When does Israel begin adding Tal Umatar (the rain prayer) in the Amidah?
In Israel: 7th of Cheshvan — about two weeks after Sukkot, when the pilgrims from Babylonia would have returned home. Outside Israel: 60 days after the fall equinox.
Question 2
You forgot Al HaNissim on Chanukah. Do you go back?
Al HaNissim is an addition, not a core requirement. If forgotten, the prayer is still valid. Don't go back.
Question 3
You forgot Ya'aleh V'yavo during Maariv on Rosh Chodesh. Do you go back?
Rosh Chodesh doesn't create a nighttime obligation for the extra insertions. If you forgot Ya'aleh V'yavo at Maariv on Rosh Chodesh, continue — the prayer is valid.
Question 4
Where in the Amidah is Ya'aleh V'yavo inserted?
Ya'aleh V'yavo is inserted in the Retzeh blessing (Retseh) — the 17th blessing that deals with the Temple service and Israel's relationship with God.
Question 5
Can you add personal prayers for a sick person during the Amidah?
The Rambam encourages adding personal requests within the appropriate blessings. Add healing requests in Refa'einu, parnassah needs in Bareich Aleinu. The structure accommodates personal prayer.