The parchment of a mezuza contains the parshiyos of “Shema Yisrael” and “V'Haya Im Shamo'a” written on the skin of an animal by a sofer Sta'M. The parchment needs to be protected by the weather which can easily invalidate it which is why it is placed in a case.
The source of the mitzva is in the book of Devarim (6:6-9), “And these things which I am commanding you today should be on your heart … and write them on the doorposts of your home and gates.” Likewise, the mitzva is to attach mezuzos in the doorways of entrances (Devarim 11:18-21), “And place these words on your hearts and on your souls … and write them on the doorposts of your house and gates so that your lives and the lives of your children increase on the earth that G-d swore to your fathers to give to them, as the days of the heaven on the earth.”
WHAT ARE THE DIFFERENCES IN HOW A MEZUZA IS WRITTEN?
The difference between the types of mezuzos is in the writing. Although it is fine for sefardim to put up mezuzos with ashkenazi writing and vice versa as both are kosher, it is customary to put up mezuzos in accordance with family custom. One does not need to change the mezuzos if one moves into a home which has mezuzos that are different than your custom. However, when renewing mezuzos, it is worth changing them to your family's custom. If you have no family custom, one buys nusach sefard.
WHAT SIZE MEZUZA SHOULD I BUY?
Mezuzos come in different sizes and halachically there is no difference. At the same time, since this is handwritten work done with a quill, the smaller the parchment the more expertise is needed and the more room for mistakes. Likewise, smaller letters can more easily be erased over the years which is why it is customary for the parchment to be between 12 and 25 centimeters. One can order special sizes to fit the size of the area and the design of the house.
HOW CAN ONE BE SURE THE PARCHMENT IS PERFECT?
The parchment of a mezuza can only be checked by an expert. In general, one needs to ascertain that it was written by a certified, G-d fearing sofer on special parchment, with ink and a special quill. A computer checks it for missing or extra letters. A mezuza parchment that is torn or has writing that is printed or photocopied is not good. For this reason, it is very important to order a mezuza from a place where the checking is done by an expert before being sent to a customer.
HOW OFTEN SHOULD A MEZUZA BE CHECKED?
When preparing a mezuza for a customer, the parchment is rolled up in plastic in addition to its being protected by a case. Still, the ink can fade and the parchment can wear out over the years due to weather conditions and pollution as well as lower quality parchment and ink. A mezuza should be checked at least every three and a half years and some are particular to check them every year in Elul.
If you have any question or concerns about your Mezuzos, we are happy to help! You can contact us via whatsapp (at the bottom of the website), by email: firstname.lastname@example.org or phone: 718-778-7826.