It’s unnecessary, and it’s considered redundant.

WRONG: The teacher said “hi” to only one student, (whose name was Charlie).

WRONG: The plaintiff, (who had a strong case), looked confident at the hearing.

In 2026, I will:

Put more verbs in the active voice (1)
& use “that,” not “which”
when given the choice (2).

I’ll use “therefore” or “thus”
(but never “as such”) (3),
and I’ll throw away my “However, . . .” crutch (4).