It really depends, I'm shooting for >10 acres at the moment, but I'd prefer more like 40 with an even mix of timber and agricultural. Chickens, a couple of dairy cows, some grain crops and a substantial vegetable garden, hopefully some fruit trees and grapes.
As far as "need" goes for my goals, probably could get by with 5 acres of agricultural and 5 of timber to have a sustainable firewood and food supply, but that assumes no buffer from your neighbors, which is probably not a good plan.
As far as "need" goes for my goals, probably could get by with 5 acres of agricultural and 5 of timber to have a sustainable firewood and food supply, but that assumes no buffer from your neighbors, which is probably not a good plan.