Any covered balcony over 50 square feet requires a mezuza.
 

Each door needs a mezuza except for a:

• Bathroom, or a
• Room less than 50 square feet.

We do not normally affix mezuzot to hotel rooms, even when we would be required to (as when staying for more than 30 days).

Mezuzot must be placed on any buildings used with a person's home.

Only buildings in which people live need a mezuza, so you do not need to put them on offices, synagogues, or stores (unless people also live there). No mezuza is needed on an eruv.

Mezuzot are not required by halacha to have covers (sheitels). Covers are only for decorating and protecting the parchment; their use is recommended in the Shulchan Aruch.

A mezuza scroll should be rolled from left to right so that God's name appears on the outside.
 

A mezuza (pl., mezuzot) is a small, sofer-inscribed parchment scroll containing the two Torah paragraphs commanding us to put mezuzot on our doorposts and gates: Deuteronomy/Devarim 6:4-9 and 11:13-21 (these are the first two paragraphs of the shema prayer.)  Each doorway that is related to where people live must have a mezuza.

Mezuzot are placed on the right side of doorways as you enter in apartments, buildings, or even recreational vehicles that you rent for 30 days or more (or that you purchase/own), in which you sleep.

A mezuza has protective value in that it reminds us to think about God each time we walk past a doorway or gateway, and so the particular name of God written on the mezuza (shin-daled-yud) likewise can serve as an acronym for God's role as “Shomer dirot Yisrael”—Watcher over the dwelling places of Israel.  

By surrounding ourselves with reminders of the commandments and with objects for observing the various Jewish rituals, we can be constantly aware of what we should be doing to live our lives as Jews.
There are two categories of items used for mitzvot:

• Holy items (tashmishei kedusha), such as tefilin and its boxes, Torah books and commentaries, and Torah scrolls and covers. 
• Items used for mitzvot (tashmishei mitzva), such as lulav, etrog, and talit/tzitzit.

Women
Sacred scrolls (Torah, mezuza, tefilin) may not be written by women for sacred purposes. However, if they were written by a woman, you may study from them. You may not use them for public Torah reading, putting on tefilin, or affixing to doorposts (for mezuza).


Disposal
Both tashmishei kedusha and tashmishei mitzva should be disposed of in a respectful manner. Tashmishei kedusha should ideally be buried. Newspapers with Torah or Torah commentary must be double-wrapped and then may be put in the trash, since they contain material that should not be buried with holy writings (only a newspaper's Torah or Torah commentary contain inherent holiness).
To dispose of tashmishei mitzva, you may wrap in one layer of plastic and throw it in normal garbage.

In general, porches and awnings on the outside of a house will not qualify as being part of the house for the halachot of carrying on Shabbat if there is no eruv. The porch or awning must be in the structure of a shape of a doorway (tzurat ha'petach): vertical poles and cross beams must be on TOP of the vertical poles in order to be considered a halachically enclosed area.
Note Since these are not intended to be a doorway, no mezuza is required on them.

You may not do “expert” or “professional” work of certain types on chol ha'moed, and some types of expert craftsmen/women may not do their trades on chol ha'moed.
Examples

• You may sew or lay bricks or other such labors, but not if you are an expert or professional in those fields and you are doing expert work.
• Skilled writers and artists may not do their professional writing, calligraphy, or drawing (even for free!) on chol ha'moed. They may not do calligraphy or sofer work (Torah, tefilin, mezuza), but they may write normally.
• If you are not a professional writer or expert craftsman/artist, you may write on chol ha'moed but the preferred practice is to use a shinu'i --an altered method of writing, such as:
  • Using your other hand,
  • Holding the pen/pencil differently from normal, or 
  • Writing diagonally across the paper.

Almost all mitzvot may be enhanced by:

• Making them beautiful (hidur mitzva), or
• Observing non-required stringencies (mehadrin).

These holy writings (tashmishei kedusha) may not be thrown directly into the trash, but should ideally be buried with like items (sheimot):

• Holy writings that contain God's name.
• Parts of Tanach (24-book Jewish Bible).
• Explanations of the Torah or commandments.

However, if a printed or written page (in contrast to parchment scrolls such as tefilin, Torahs, or mezuzas) contains God's name plus secular content, it must be double wrapped in plastic before being thrown in the trash.
Do not throw into trash, even if double wrapped:

• Handwritten scrolls of Torah, tefilin, mezuza.
• Printed Torah, Talmud, siddur, books of halacha, or Torah commentaries.

Rather, put them into a sheimot collection box or wrap in plastic and bury in a place where they will not be dug up. It does not need to be a cemetery.

Double wrap and throw into trash:

• Newspapers and flyers that have Torah psukim or Torah commentaries and also have non-Torah content.
  Reason Non-Torah material should not be buried as sheimot. 
• Children's school handouts with psukim from the Torah or halachot that also contain non-Torah content (if they ONLY contain words of Torah, they should be buried as sheimot).

For disposal of items used for mitzvot (tashmishei mitzva), you may wrap in one layer of plastic and throw it in normal garbage:

• Lulav,
• Etrog, or
• Talit/tzitzit (but NOT tefilin!)

“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.