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

3 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