I like to say the band installer has to be able to count to "two".
I just was reminded last week how much fun it is when the band misses one or both nuts- young man tried his hand at banding his babies and I had to fix nine mistakes now that they're 500+ lbs.
i've knifed and pulled the cords on countless calves of all sizes over the last 37 years. I've started using an XL bander (pre-cut rings) the last year or so, and most of the time can do it quicker than the Newberry knife. Often don't even need to tail the calf. And it's easier on my shoulders. Callicrate bander on the ones that are too big to get an XL on.
But a lot still get knifed, 30-40 days for the bag to drop after banding is too long for some guys.
