If two non-adjacent compartments (e.g., 1st and 3rd) of the head Tefillin are damaged, are the Tefillin valid?

If two adjacent compartments of the head Tefillin are damaged (torn), are the Tefillin valid or invalid?

5 opinions across 3 eras

What defines Tefillin as 'new' vs. 'old' for purposes of the damaged-compartment rule?

3 opinions

If three compartments of the head Tefillin are damaged, are the Tefillin valid?

2 opinions

If the stitching of the Tefillin is severed, when are the Tefillin invalid?

4 opinions across 3 eras

Must the leather of Tefillin straps (retzuot) come from a kosher animal and be processed (tanned) for the sake of the mitzvah?

3 opinions

Must Tefillin straps (retzuot) be black, and on which side?

3 opinions across 3 eras

Must the blackening of Tefillin straps be done by a Jew and lishmah? What is the status if done by a non-Jew?

4 opinions

If a Tefillin strap is severed, may one repair it by stitching, and does it depend on where along the strap the break occurs?

7 opinions across 3 eras