This quote is often cited by traders, but I believe it applies just as well to investors. At the end of the day, whether you trade or invest, it’s still a game of capital.
You should always leave room for the possibility that you’re wrong in any position. That’s what allows you to cut losses decisively based on logic, not emotion.
In practice, before making any investment, I always draw out a full picture that includes both a Bull Case and a Bear Case. You need to understand what you’re holding, otherwise “hold to die” becomes literally holding so you die, rather than holding with conviction until the end.