I heard that the Rambam in his commentary to the Mishna mentioned cases where the custom of the place was different, one such place being יָוָן, where men didn't cover their heads with their tallitot, ...
I once heard from a friend that if you are wearing a Tallis at night, for example as the Chazan for maariv or everybody at maariv of Yom Kipppur, you should not cover your head with it as some people ...
What is the source for checking one's tzitzis while the talis is over one's right shoulder: isn't the halacha just to check the knots and strings? Can't the checking be done on a table?
Why is it that most Ashkenazim that are not married do not put the Talis over their head?