Question:

I've noticed that in some synagogues the cantor always wears a tallit as well as those who are called up to the Torah, and in other synagogues a tallit is not worn in the above scenarios. What is the rule of thumb?

Answer:

In most Jewish communities, those who are honored with leading the congregation in prayer, or those who perform a public religious function such as receiving an aliyah or lifting the Torah, don a tallit. This is considered to be respectful of the congregation. This custom applies to: a) Unmarried men, who according to Ashkenazi tradition do not wear a tallit. b) The afternoon and evening prayers, when even married men do not wear a tallit. c) A person not participating in the prayer services who receives an honor.

In many other communities — Chabad included — this custom was never adopted. Thus, in these communities not wearing a tallit obviously isn't considered a disrespect for the congregation.

If praying in a synagogue whose custom is different than your own, you may follow your own custom, provided that it won't cause any friction or quarrels. The exception to this rule is wearing a tallit during evening services, for those who traditionally do not do so. According to kabbalah wearing a tallit at night can have negative consequences, and should be avoided if at all possible. In such an instance, politely declining the honor of leading the services is probably advisable.

Rabbi Dovid Zaklikowski,
Chabad.org