Reply #37: Tefillin are used during prayers, if I understand correctly,

[MineralMan]

for the most part. I think there are some ultra-orthodox who wear them more often than that.

Orthodox kids get their tefillin at their Bar Mitzvah. I'm not sure about other aspects of Judaism.

I'm an atheist, so my knowledge of this is just based on general background information about religious practices. I could find out more details, but it's not a high priority for me today.