I am knitting a child’s sweater and the pattern calls for a 9 stitch 1x1 rib button band. It wants me to knit a band with a length to the back of the neck, and then a second band to the back neck for the other side and then join the two together. Any compelling reason why I can’t knit the band all in one stretch?
@annekepoot I’ve made many sweaters, and never had a pattern like your describe. I’ve always had one button band all around the neck to the other side.
A join might add a little structure that keeps the button band standing up, but I don’t know if that’s really needed for something nine stitches wide.
Yeah, I think I’m just going to go ahead and knit in one piece - my joins never look that wonderful! 
I’ve seen many vintage patterns that say to do it that way. not sure why.
But it should be fine to do all in one piece.
I look forward to seeing pictures! Hope you post some.