At the "sub-village" level, you have to remember that they don't exist in isolation; each of the tiny communities is within a day's walk or less from a larger community. So the only things it needs are things that it can't wait 4-12 hours for...
A lot less than a day's walk, in any area suitable for agriculture. You can only plough fields that are within the radius at which your animals can be taken/brought back within an hour or so, since you want to have enough time to get some work done and the animals require rest and time to eat (which oxen won't do in the dark). At the same time, no one wants good agricultural land to be wasted, so the fields that are just a bit too far away for you to plough are likely ploughed by the neighbouring village/hamlet/thorp. In England and France, you're looking at roughly a mile between villages. Market towns are further apart, 10-20 miles. That's where you go to sell/buy things that aren't available in the village, and which the last pedlar didn't bring through.
Edit: This is in areas of arable farming. Other areas the density is noticeably lower.