As a nerd, I looked for the etymology of "fish or cut bait." See, I thought I knew what it meant, but I'm often wrong and (more often that that) learn a lot by looking stuff up. (Thanks, Mom!)
Lots of times, when people look for the origin of a word or expression, the word or expression can be traced back definitively. Other times, there are different theories about how the word or expression came into use. "Fish or cut bait," for example!
According to a few not-exhaustively searched internet sources, this expression may have/probably started with fishermen who were faced with a choice to either keep a fish or cut it up for bait. Another explanation (one that I have been using) is that a fisherman is faced with a decision to either keep fishing (in an unproductive spot--hoping the unproductive trend will change), or cut bait--meaning cut the line, losing the bait, in order to try fishing in a different spot. In other words, to keep trying, or to cut your losses.
When I looked it up, I was pretty surprised that this isn't a phrase that everyone agrees on!
Phrases.org.uk says that this expression is "one of the US phrases that the rest of the world doesn't understand," which makes me smile. I'm pretty sure the person who wrote it was smiling when they typed it in, too.
Anyway. To cut to the chase, "fish or cut bait" means either to decide whether to continue or to cease (and in stopping, lose some vested interest), or to decide between two activities and get started. I mean, maybe. I could be wrong.
***
