Question

Are speaker tags required everytime when speaker changes?a Everytime b Only on some occasions
c never

Answer 1

b. only on some occasions

Answer 2

A speaker tag is his/her identity with his name and probably designation inscribed on it. During any changes or replacement of the current speaker, it should be mandatory that the new speaker should wear his tag for the proper identification by others.  

So, the answer to your question is a) Every time.