Make sure your Koi get enough to eat with an automatic feeder. Going away on vacation isn't a problem with an automatic Koi feeder or a demand Koi feeder. Just load it up with Koi food and go.
If you want your Koi to grow large, fast then you should feed them several times a day but small amounts. Having and automatic Koi feeder helps by getting small or large amounts of food into your Koi on a set schedule. Another good reason to use an automatic Koi feeder or demand Koi feeder is because it helps your bio-filter to process smaller amounts of waste more frequently during the day rather then 2 or 3 large feedings per day.