@eirene_belle: At home where I grew up, it used to be simpler. I had several trees from which I collected the olives, took them to an oil press and the next day I went to get the oil. You may be surprised, but I only had a few trees and there was always oil left for the following year, this in the conditions in which food was cooked at home every day. In good years, the average production was about 50 kg per olive tree, equivalent to 6-8 kilos of olive oil. Now there is always a little left.