Came across this and set Uncle8888 thinking loud too . Hmm ... and then ..
To answer this question: How long?
First, let us try to understand 3Ms in Investing: Method, Mind, and Money Management
Our Investing Mind: The Winner and Loser investing mindset and the way we as retail investor may like to think on winners and losers.
The Loser Investing Mind
When we bought a stock based on our investing Method; we will expect our self-defined decent yield with some capital gains in the near future; otherwise we will be waiting at the sideline for the "right" entry price.
But after we have bought; the stock price went south and farther south. Soon; we will be holding on this big loser. When we have held on to big loser year after year. It is matter of time, one day; we will change into Loser investing mind - I want to get out when I can! ......