It is traditional for rabbis to grow beards but it is not required.

You may not normally ask multiple rabbis for halachic decisions about different questions, but if you do not have a primary rabbi, you may do so.

If you forgot to make an eruv tavshilin, you may rely on the eruv tavshilin said by the local rabbi only once in your lifetime.

Rabbis may have their congregations add Psalms/tehilim or other prayers to standard services.  

You may not generally ask different rabbis for their decisions of halacha in order to get the answer you want.  You may also not ask a specific rabbi a question based on your expectation that he will give you the answer that you are seeking. But if someone asks you to recommend a rabbi, you may refer him or her to a rabbi who will give the answer that he or she would like to receive.

Ideally, only one mourner should say kaddish, whether mourner's kaddish, rabbis' kaddish, etc. Any kaddish said by more than one mourner should be said in unison.
 

Some communities end Shabbat 42 minutes after sunset, which is when some rabbis in New York observed that it gets dark. At other latitudes, the interval may vary considerably, from shorter toward the equator or much longer toward the poles.

It is praiseworthy to tell the story of Passover even if you know all the details and interpretations (as did the great rabbis of the Talmud), because of the principle of “in order to remember” (lema'an tizkor): that we should remember everything God did for us when taking us out of Egypt.
The Three Discussion Points
The most important part of the seder is discussing:

• Passover offering (Pesach),
• Unleavened bread (matza), and
• Bitter herbs (maror).

These three segments should be read from the Passover hagada in the Hebrew.  If anyone does not understand the Hebrew, these paragraphs and the concepts they express must be explained in whatever language he or she can understand.
Children at the Seder
Children are an integral part of the seder.  We try to get children to ask questions and then we teach them the answers.  The Torah says to do this!
Acknowledging God's Miracles
We acknowledge God's miracles in sending the plagues against the Egyptians and their gods and in taking the Children of Israel out of slavery and Egypt.
Telling Our History
We tell our history beginning with Jacob (Yaakov) and Laban (Lavan) and on to slavery and, finally, to achieving freedom.
 

“Be holy because I, the Lord your God, am holy.” Leviticus/Vayikra 19:2
 
Halacha ("The Way To Go" or "Way to Walk") guides proper Jewish behavior in all aspects of life, each day of our lives--not just in civil laws or court situations. Halacha teaches us how to behave with our families, relatives, and strangers as well as how to fulfill our religious requirements between ourselves and God.

To fulfill our role as a holy people, we imitate God's actions. Examples are visiting the sick, welcoming guests, giving charity, refraining from creative activity on Shabbat, and promoting peace between husband and wife (shalom bayit).

The true reason for following halacha is because God commanded us to do so.  We observe halacha to please our Creator and to become spiritually close to Him by doing His will and imitating His actions.

Like the word for the whole body of Jewish "laws," each rule of how to act is called a halacha (plural, halachot).

Where Do Halachot Come From?

Although you will find halachot on this site that were born only a few days or a few decades ago, the body of halacha has been around since before creation.  "God looked into the Torah and created the world," says the Zohar, and so we find the Patriarchs followed halacha even before that great law book, the Torah, was given on Mount Sinai four centuries later.
 
Many halachot are specified in the Written Torah (Jewish Bible). These halachot correspond to fuller and more detailed halachot given orally (Oral Torah) to Moses on Mount Sinai to explain the Written Torah that he received at the same time. Many halachot could not be understood from the Written Torah without the Oral Law (for example, what should be written on a mezuza scroll?) and many common practices such as making kiddush or what tefilin should look like are to be found nowhere in the Written Torah.
 
Since the Torah applies to all generations, the Torah specifies that there be wise and learned people to decide how to apply halacha to the situations of the day.  Halachot can be found in sourcebooks such as the Mishna, Gemara, their commentaries, Shulchan Aruch, Mishna Berura, and responsa (questions and answers originally sent by letter and now, occasionally, by email or SMS!) of later rabbis.
 
Sometimes a custom becomes a halacha, sometimes not.  For example, the original halacha for tzitzit was that a Jewish man who wears a four-cornered garment must have tzitziyot on each corner.  The custom, which has become universally accepted and now has the force of halacha, is that Jewish men wear a four-cornered garment in order to be able to fulfill the commandment of wearing tzitziyot.  An example of a custom that did not become a halacha is that some men and boys wear their tzitziyot outside of their shirts and pants.

Levels of Halachot

In halacha, there are three levels of what to follow or observe. They are differentiated on this website by the following terms: 

• “Must”:  Halachot that are generally non-negotiable except in extreme situations;
• “Should”:  Customs that have been accepted by the entire Jewish world (or major segments of it) and that may be overridden when necessary, sometimes even if not extreme circumstances; and
• “Non-Binding Custom”:  Customs that are not universally followed and that do not need to be followed except by people who have the tradition to do so.