Shanah Tova. As you are well aware, that is the greeting for Rosh Hashonah. The greeting for Yom Kippur is different. G’mar chatimah tova is the greeting. It means “A Good Finish”, though it is usually freely translated as “May you be inscribed for Good in the Book of Life.” Yom Kippur ends the Yomim Noraim, the 10 Days of Awe. According to tradition, these are the days God examines each of us to determine where God will put us in the Book of Life. Yom Kippur is the day God writes the Book of Life, thus the greeting.
Shlugen kapporis. We associate this term with swinging a chicken around ones head while saying, “this is my substitute, my vicarious offering, my atonement. This cock or hen shall meet death, but I shall enjoy a long pleasant life of peace” on the day before Yom Kippur. A cock, hen, geese or even fish were used as one could not use any animals which were used in the Temple sacrifices. The idea was one transferred ones sins to the animal. Today, due to concerns for the animals, coins are used which are then donated to charity.
Yom Kippur never falls on a Friday, Sunday or Tuesday.
If Yom Kippur were to fall on a Friday, it would be impossible to prepare food for the Sabbath. If it were to fall on a Sunday, it would be impossible to do on the Sabbath all that is necessary to prepare for the fast. If it were to fall on a Tuesday, Hoshanah Rabbah would fall on the Sabbath and the requirement that aravot (willows) be beaten would not be able to be observed, for this would be in violation of the Sabbath.1 Hoshana Raba is the last day of Sukkot. Reform Jews do not practice anything special on that day.
Any religious requirement that might endanger ones health is suspended at any time. For example, as a diabetic, it could be dangerous for me to fast. Therefore, that requirement does not apply.
One requirement which does apply is to wear a tallit during Kol Nidre, even though a tallit is not worn in the evening. It is worn to emphasize the extra holiness of the service.
The book of Jonah is read on Yom Kippur because of two themes. One is it shows the universality of God. The other is, it shows, by Nineveh being spared, that all people have the ability to repent.
Herring is usually served at the break the fast. This is so one gets thirstier and drinks enough to replenish the water lost during the fast.
G’mar Chatimah Tova. May you all be inscribed for a good, happy and peaceful year.
1 The Jewish Book of Why Alfred J. Kotlatch