By Jim M
True a closet is a closet. However, if a arc fault started in the closet light would the sleeping people be immune to the fire just because it is in the closet? IMO peoples lives are too special not to add the protection to the closet.
Jim putting the closet on an AFCI might
help and you are free to do so.
But is it required?
No it is not required which is what the question was.
I would be willing to bet PCBelarge goes beyond code minimums many times, but his answer in my opinion is right on the money.