Sweater Seven, Installment Two: Alafoss

So the body and sleeves were joined up, (almost) no problem. 

I did somehow end up one stitch short in the body, so I did an increase (kfb) under the arm, where it will hopefully not be noticed.  What wouldyou have done in this situation?  I always go through this thought process:

Where did I lose that stitch?  It's possible I cast on the wrong number, but given that the bottom hem consisted of ribbing,  I would have noticed if I'd been off by one stitch.  Did I drop a stitch somewhere? If I did, I need to pick it up.  Did I do a weird decrease somewhere?  If it's close to my live edge, it might be easy to fix.  In the case of this sweater, I still haven't figured out where I lost that single stitch.

Do I really need to have the exact number of stitches?  In this case, yes, because I was going to be knitting the yoke from a chart with a specific number of stitches.

Is it worthwhile to rip out and re-knit?  I went back and forth on this one; because the gauge is such that each individual stitch occupies approximately a quarter of an inch, one stitch could make a noticeable difference in the overall circumference of the body.  If I were dealing with, for example, a fingering weight yarn, each individual stitch might only occupy a tenth of an inch, and one missing stitch won't make a noticeable difference in the overall dimensions.  However, the fabric isn't very dense, and it's pretty stretchy, being stockinette, so I think the single missing stitch won't be a big deal.  I chose not to rip and re-knit.

Where can I hide an increase?  In the case of this sweater, the underarm area makes a great place to hide an increase.

This isn't really rigorous knitting, which bothers me a bit, but it is real-life knitting, at least for me.  What do you do if you have an extra or a missing stitch?