Originally Posted by stefcap
I was thinking -
I am knitting the front and then the back, then sewing them together.
Should I just do the Provisional CO, so I can do a 3-needle BO to join, rather than having to pick up all the sts on the CO end to join.
Unless you're knitting a sweater sideways (which is a legitmate method) usually you're not joining your CO edges together. The CO is usually the bottom hem (or the top if you're knitting from the neck down) of the sweater. It's the selveges (sides) you will sew together, usually using mattress stitch.
You CAN use a 3NBO for a seam at the shoulders though (the left and rigth fronts to the back), just don't bind off the top stitches of the shoulders of the back and fronts.