Before making a purchase a consumer should do some research to check the quality of the product. Unfortunately, when purchasing STA'M, (acronym for Sefer-torah, Tefillin And Mezuzah) many people are not trained to do the proper research. They are unaware of the laws concerning the Mezuzah scroll, and therefore, tend to rely solely upon the merchant and purchase whatever is suggested.
As a result, many Mezuzos bought by the layman do not conform to Halachic requirements. In turn, the people affixing these Mezuzos are not fulfilling the Mitzvah.

This article is offered in the hope that it will give the reader a very basic understanding of the Mitzvah of Mezuzah. Although the laws of STA'M are complicated there are certain basics of Mezuzah that everyone should know.

The Text
A Mezuzah scroll contains two paragraphs, handwritten on a single piece of parchment, by a Sofer (scribe). Each paragraph contains a portion of the Torah referencing the commandment of Mezuzah.
They are as follows:
1. Sh'ma (Deut. 6:4-9), affirming the unity of G-d and our mutual bond of love.
2. VeHaya Im Sho'moa (Ibid. 11:13-21), declaring man's responsibility toward G-d.

The Mezuzah scroll is rolled up and placed in a protective case. It is affixed to the right hand doorpost of each room in the house (except bathrooms).

The Parchment
The preparation of the Mezuzah scroll begins with the parchment. Parchment is the hide of a kosher animal, that has been soaked, stretched and sanded Lishmah - with the specific intent of writing religious scrolls. If "Lishmah" is omitted, even the most beautiful and carefully written Mezuzah scroll is invalid.
The parchment should not be coated with a glaze. The glaze tends to peel when the Mezuzah is rolled, causing the letters to crack and become invalid.
The parchment is then scored with lines - Sirtut. This is to guide the Sofer in writing.

How long does it take to write a Mezuzah?
It usually takes 2-4 hours to write a Mezuzah. Consider the disappointment of the Sofer who, upon completion of his work, discovers an error which invalidates his hours of work. An unscrupulous individual may make an improper correction which could never be detected, but the Mezuzah nonetheless would still be Posul - invalid.

Law of K'sidron
Tefillin and Mezuzah must be written K'sidron - in consecutive order. If a letter was omitted, it cannot be inserted later. In a Sefer Torah such corrections are permissible. However, in Tefillin and Mezuzah it is Possul - invalid.

The Sofer
Mezuzah must be handwritten by a Sofer who is knowledgeable in the Halochos of writing STA'M. He should be an expert technician as well, for the task of writing Mezuzos is a difficult and responsible one. Each letter must be properly formed, and must be complete, without disconnections or cracks. Lines and letters must all be properly spaced. Each letter must be completely surrounded by parchment -Hakofas Gvil. No two letters may touch.
One of the most important aspects of a Mezuzah is the Sofer. He must be a man of integrity. To insure proper Kashrus and reliability, one should purchase Mezuzos from dealers and Sofrim who have the highest recommendation, and who are, themselves, knowledgeable in the field of STA'M.

Hiddur Mitzvah
Beautifying the mitzvah. Each Sofer has his own individual writing style. While all may be technically Kosher, beauty and consistency may vary considerably. The skill and beauty of the writing will vary from one Sofer to another, as seen in the product samples. Hiddur Mitzvah has financial implications as well. The more beautiful the Mezuzah, the greater the cost.

How often do I need to inspect my Mezuzos?
Mezuzos should be checked at least twice during a seven year period. Even if a Parshah was written correctly and later a letter became incomplete or cracked, it becomes Possul.
Mezuzos should be thoroughly checked by a competent Sofer.
The reward for the proper observance of the Mitzvah of Mezuzah is great. The Torah ascribes long life and protection to the dwellers of the house that observes the Mitzvah properly. It is a relatively easy Mitzvah to observe as we are required only to affix it once. As long as the mezuzah remains on the doorpost, we are fulfilling the Mitzvah twenty four hours a day. You are doing the mitzvah anyway -make sure you are doing it right.