GUEST of 02:43 today, I stand corrected -- more or less.

I completely forgot about opera as a subset of classical music, and I certainly should have mentioned jazz as well as (orchestral) classical as TWO genres where vocals are not necessarily expected.

On the other hand, I see Duane Eddy and the great John Fahey as exceptions that *prove* the general rule.

As many participants seem to have agreed, the answer to the thread-title question is: All musical acts don't HAVE to sing, but they'll find it easier to please a wider audience (i.e., to get more gigs) if they introduce at least a few vocal numbers.

Plus which, if they give it a try, some players might discover that it's a lot of fun to sing!