When looking to purchase Mezuzos or Tefillin there are two essential points that you need to take into consideration 1) The Ksav/ The style of handwriting 2) The Sofer / The Scribe.
1) The Ksav
Before purchasing Tefillin or Mezuzos , the first thing you need clarity on is the Ksav. What is your background and family customs, there are different styles on how the letters are formed according to your family traditions namely they are:
Different Kesavim; Beis Yosef, Arizal, Vellish/Sefardi and Alter Rebbe.
A) Ksav Beis Yosef: The letters formed according to the way the Beis Yosef describes the letters in Shulchan Aruch. This Ksav is used by Ashkenazim.
B) Ksav Arizal: Although most of the letters are the same as Beis Yosef, there are a few which are different. This Ksav is generally used by Chassidim.
C) Ksav Vellish/Sefardi: Is used by Sefardim, old Sefardi Ksav is a problem for someone of Ashkenazi descent because in many old Sephardi Ksavim the yud is missing the Kotz Rabbeinu Tam (a little Protrusion coming out on the bottom left side of the yud) however the Chida instituted that even Ksav Velish/Sefardi should have the Kotz Rabbeinu Tam. Therefore, almost all Sefardi Ksav today have it.
D) Ksav Chabad: Used by Chabad Chasidim letters were designed by the first Lubavitcher Rebbe, Rabbi Schneur Zalman of Liadi also known as the Bal Hatanya it is a blend of Sephardic and Arizal Ksav.
In Mezuzos you are fulfilling the mitzvah at least bidieved if you don’t follow your custom, but in Tefillin there is more than just the style Ksav there can be a real halachic issue with the shiur parshios between “Shema” and “Vehoya im Shamoah” which could prevent you from being allowed to make a Bracha. Therefore in Tefillin it is essential that you follow your custom.
2) The Sofer
When it comes to purchasing Teffilin or Mezuzos, it is extremely important to purchase from a certified Sofer that is a Yorei Shomaim. For what use is a beautiful Ksav if it was not written according to Halachah. When it comes to writing or fixing there are many complex Halachos which if not followed can render whatever was written possul. Many mistakes cannot be detected by even the most trained eye after the fact.
For example if the Sofer forgot to express the proper intention prior to writing a mezuzah or a pair of parshios for Tefilin then they are possul. So too a letter that was written improperly and is corrected by scratching away ink, for example a daled that needs to be a reish, scratching off the top right to round it off like a reish would make it possul, since the letters need to be written. Because the Torah says “Uchesavtam” “And you shall write” it does not say “Ucakaktom” “You shall scrape”.
Such a mistake cannot be corrected because Hashems name is already written furtherSimilarly adding ink to correct a letter or adding a missing letter out of order, I.e. if the Sofer has already written further, would make it possul, because it says “Vehoyu” and the Medresh explains “Behaviosom Yihiyu” which means that the order that the letters are in, is the order that they have to come about in, so if for example the sofer wrote the word of shema then he realized that the shin was possul he cannot just correct it he must first erase the ayin and the mem then correct the shin and start again. If Hashems name is written after the mistake it cannot be corrected, because in order to correct you would need to erase all written after the mistake or missing letter and Hashems name cannot be erased.Therefore buying from a Certified Sofer is very important because just as it is important know that the Sofer be a Yiras Shomaim/G-d fearing Jew. It is equally important that you know he is fluent in the Halachos.
What makes Tefillin and Mezuzos Mehudar?
I have a large selection of Tefillin and Mezuzos some more basic and others are very Mehudar. With a price range of $55 to $200 for a Mezuzah. And Tefillin from $425 to $1900.
A nice Mehudar Mezuzah takes a Sofer approximately 3 and a half to 4 hours to write, and Tefillin can take as long as a week. Now because so much time and effort is put into the writing , a nice Mehudar Mezuzah can easily cost $90, while some can reach as far as $200. Since these are not machine made there is no standard run of the mill price, the more Mehudar the writing is it is the more it will cost.
Mehudar means two things:
A) Aesthetic beauty, the Torah says “ze keli vi anveihu” which translates to “this is my G-D and I will glorify him” we learn from here that it is proper to adorn the mitzvos, that our observance of the mitzvos be a beautiful as possible. In our terms here it refers to a beautiful Ksav.
B) More importantly it is referring to the Halachik aspect, to fulfill the mitzvah on the strictest level. A level that every Halachik authority would agree is Lechatchila and that it is the most kosher it could be.
But remember just because a Mezuzah or Tefillin is not Mehudar does not mean it is not Kosher. There are several factors that make a Mezuzah and Tefillin Mehudar. The more they have the more Mehudar they are:
1) Beautiful Ksav. Simply it means that the letters are beautiful, their length and height are symmetrical, and the Sofer followed closely the intended Ksav and did not veer off.
2) That the letters are formed properly and that there never was any doubt over the form of any of the letters.
3) None of the letters are touching from the time of the writing (there are opinions that say that any letters touching from the time of the writing even if they don’t loose their form or form another letter is invalid. Although the Halacha is not like them for Mehudar we want to encompass all Halachic authorities).
4) No questionable spacing, the words and letters need to be spaced properly and evenly as to assure which letters belong to which word.
5) The letters have the crowns written on the letters as the letters are formed. In many cheaper Mezuzos the words are first written, and then later someone else adds the crowns afterwards.(there are opinions that say they need to be formed as part of the letter.)
6) All the letters that need, have additional crowns as specified according to Kabbalah.
7) According to Halacha the letter Lamed has two crowns/tagim. Kabbalah explains that the tag on the right side corresponds to kindness, and the one on the left, to severity. Consequently, it is of utmost importance that the right tag be taller than the left one, ultimately drawing down kindness from Above.
8) The names G-D on the back of the Mezuzah are in the correct place corresponding to the names of G-D on the front of the Mezuzah.