A really good book on this topic I recently read: Quit, by Annie Duke.

The book boils down to "Calculate EV of your decision, try not to fall prey to sunk cost fallacy". But it makes the lesson really sink in which is nice.

My favorite bit was her sharing the research that you cannot avoid sunk cost fallacy. Humans don't work that way it seems. What you can do instead is to pre-commit to quitting when certain conditions are met.