Especially using the tier method on the 360 and homemade types. Some people will say they go 1-4 months then harvest, I dont. I go by how many worms are in the bottom harvest tray. When most have moved out and it looks like maybe less than 50 remain I will harvest When so many have left that tray they have used up all the food/debris available. There will always be some worms left in the harvest tray, get used to it. Only one time did I do a harvest when there was maybe 10 worms and I relate that to 0 worms when you know there are thousands in the entire system.