Suppose a stock is at $10, and it is giving out $0.50 dividend, which is 5%, and you bought it.
Then a couple of years later, it rose to $20, and is giving out 5% dividend, which is $1.00, but to you, it is like a 10% dividend, because you only put $10 in.
Then a couple, or 3 to 4 years later, it rose to $40, and is giving out 5% dividend, which is $2.00, but to you, it is like a 20% dividend, again because you only put $10 in.
At this point, if 20% is something that you'd be satisfied, should you consider it a 20% dividend stock, and never sell it for the rest of your life as long as it is $40 or higher and giving out 5% dividend? Or is this idea flawed, because you could easily move the money to another stock that gives out 5% and it is the same absolute dollar amount.