For Gunpowder & Lead: Sunk Costs
I don’t doubt that many would make their recommendations on this basis. If you have put a lot of time and effort and energy and sacrifice into something, it is understandable that you’d want to see it through, but there comes a point when it might become clear that your approach isn’t working, and at that point it is irresponsible not to consider changing it. Sunk costs are not a reason to do anything.