Joe of Forum coins says his collection and inventory are one of the same..... I feel a bit like that sometimes..some of the coins I have to sell will be with me for 5 years or more, so I do get to know them....
I know more than one dealer whose price structure is based on how bad they dislike the coin. If they don't want to sell it, they ask 20x what they paid but coins they don't like and are tying up cash go for 1/2. It is a fine business plan if you are in it for the hobby. I knew one dealer who bought tables at shows wholly for social reasons and didn't care if he sold anything or not. When money is not an issue, you can play by your own rules.
Could you sell your favorite coin for 10x-20x what you paid for it? What's the lowest you'd part with it for may be a better question for some coins.
It's an excellent strategy, your best/nicest piece is offered for 20x its value, you sell it, great deal, you don't... so what?