I usually keep 5 feeders out. Last summer I was feeding a gallon of sugar water a day with hundreds of hummers. This summer we had about 40 hummers earlier, but are now down to about 15. They seem to be most active early in the morning and just before sunset. I do rotate the feeders so each one is cleaned and fresh sugar water put in every other day. I look forward to August when they will be coming back south, stopping over to refuel at our feeders before heading further south.