Well this is rough carpentry because of location, location, location in real estate, but having owned house and land from 1/4 acre to 202 acres, can speak from some experience and reflection.
For country living I'm kinda in the camp that says 10 acres is an absolute minimum. Ideally 20 acres or more, way more, even, because I'd want a barrier against development encroachment and some breathing room to hunt and do some target practice.
I'm tired of moving after a lifetime of it, so our next move may be our last before hospice (yikes!). That being the case, and to remain true to your question, I'd say 20 acres plus. YMMV.
