The cardigan I’m knitting calls for BO on the shoulders and then seaming the pieces together. I’d like to do a three needle BO instead and have saved live stitches.
The pieces have a cable pattern to them. Can that be a reason not to do a three needle BO? 
Thanks for reading! 
I do three needle bind off on everything, regardless of the pattern. When there is a stitch pattern or color pattern on the front and back, you can match them up stitch for stitch and it looks wonderful. Even if it’s only on one side, 3nbo is still preferable, in my opinion.
I was hoping for just that answer from you, Ingrid! 
I thought I read somewhere that a 3nbo wasn’t recommended for pieces that had knitted patterns in them but I couldn’t see why it’d be worse than seaming the pieces together…
Thanks Ingrid!
Oh, I agree! I can’t imagine how any sewn seam could look better.
The only time I haven’t used a three needle bind off {ANYTHING to avoid seaming!}, was when the shoulders had a graduated bind off over two or three rows… next time I find a pattern like that I’m gonna be bugging everyone on this forum how to do short rows so that I can do the TNBO!
Dang, if only I had known that! So the pattern I have says
Bind off 14 st at the beginning of the next 2 rows. Put remaining 24 stitches on a holder.
Just stop there? How would you knit those 24 st in the middle?
Put 14-24-14 stitches on their own holders?
I just finished the back and have cast on for the sleeves, haven’t even started the left or right fronts yet.
Those are probably for a collar or some other type of neck finishing that you will do later.
Just stop there? How would you knit those 24 st in the middle?
Put 14-24-14 stitches on their own holders?
That’s exactly what you do. Then when they say to sew the shoulder seams, you do the three needle bind off. The center ones are used for the collar.
So it’s not crucial to knit/BO those last 1 2/3 rows?
I suppose it’s a total pain to rip out BO stitches? Just consider it a lesson learned and try the 3NBO next time? Now I want to knit two swatches just to try it! LOL
Once you get the final bound-off stitch out, the rest pop out with no problem.
I’d probably add one knit row for the bind off row, but I don’t think it makes that much difference.
If the shoulder is bound off in graduated steps you can either just do it straight, or do short row shaping for the slope of the shoulder.
If all of your bind offs for one shoulder are one one row, and the next instruction for that part is to sew the seam, I would leave it as is, and do 3NBO.
I suppose it’s a total pain to rip out BO stitches?
I have done it with smooth yarns. I’ve also done it once with a novelty yarn, but that took a lot of work and a lot of earplugs for my kids’ ears.