Hi Steve,
What Steve C said.
But also, I have a mental, and written, "ranking" of the koi we have, with always one or more "on the bubble". Shila would never want to get rid of any, but at times have done so. There definately is a "sentimentality" factor. The ranking changes a bit year by year, mostly in the bottom half. Most definately, the results we see can affect our koi husbandry practices. An example, we used to use Hikari Excel food alot of the year as I had heard "it's the best". Well, for us, it is the best only in short doses. The heads were pink when I fed it too much, which upon further research is to be expected. So now we use it as part of our show prep routine. 4 months b4 a show we feed excel for about 6 weeks and then a 6 week period of heavy refresh clay and Hi-Silk to help the whites.
Absolutely, like many people we have a "picture" in our minds of how we hope the koi will develop, but of course they do not always live up to that. Sometimes it is pattern, sometimes body, sometimes skin, but those are the things always evaluated, not just at "bowling time". The standards are the same as when we buy koi, with the added sentimental factor