Tying and caring for your tefillin

Tefillin do not like changes in humidity or temperature. Putting them on top of a radiator is not a good idea. Neither is wearing them when you have wet hair, or when you are very sweaty. Also, ideally don’t carry them in a backpack with an unreliable water bottle.

Tying tefillin knots

Rabbi Dan Rosenberg has made a series of excellent videos showing how to tie tefillin knots. Before tying any tefillin knots for real, remember to say “leshem kedushat tefillin,” to make it absolutely clear to yourself that this is for real and not just practising or messing about. Intention and focus are important.

Tefillin aren’t kosher without the knots, so tying the knots is in the same category as making the housings or writing the parchments – it must be done by a suitable Jew. If you are non-egalitarian, you must have a man tie your knots, even if the only available man can’t do it as well as you would yourself.

Fitting tefillin

Tefillin need to be fitted properly. The strap of the head tefillin should be just the right length. The knot needs to be at the base of your skull, and the tefillah itself should fall above your hairline. If you’ve done it right, it will feel somewhat precarious. This is OK.

When you buy tefillin, borrow tefillin, or get a drastic haircut, you should check whether the knots need adjusting. (If you borrow tefillin and adjust the knots, it is good manners to adjust them back again before returning them, provided you are kosher to do it.)

Using your grandfather’s tefillin

They’ve been in your family for fifty years, they’ve not been checked in all that time, but you’re emotionally attached to them.

They really ought to be checked; time can work some severe ravages on tefillin, and ideally you want to be wearing kosher tefillin.

If they aren’t kosher any more, you may be able to get them repaired. The bizarre way consumer economics work, it is usually cheaper to replace than to repair, but obviously if you are especially attached to a particular set of tefillin, you would rather spend the extra money on repair.

Not all soferim can do this. Repair is hard, especially on grandfathers’ tefillin which are usually teeny tiny. So if a sofer tells you that they can’t be repaired and you should just buy new ones, get a second opinion – it’s quite possible that he can’t repair them but someone with more expertise can. Start by saying “I was told that these can’t be repaired, is that really true?” – psychology dictates that if you put it like that, he will make the effort to prove the other guy wrong!

Even if one part can’t be repaired, you might be able to repair other parts. Perhaps the parchments are still good, but the housings will have to be replaced, or whatever – tefillin have many components and some continuity ought to be possible. If the sofer’s primary interest is selling you a new set, of course they will tell you the whole lot should be replaced, but if they are a ben Torah, a decent person, they will work with you to keep as much of the old set as possible.