How well do you protect villagers?

Depends on the villagers' trade. Sometimes it's not worth protecting a village, or even a particular villager, if their offers are bad. And very often, I would just pick up food (carrots or potatoes) from their farm, and leave. If I cared about a particular villager, I would just trap them so mobs can't attack them. I find it time consuming fortifying the perimeter of an entire village, so that's not really worth doing; the least I would do is place torches around, and maybe set up an Iron Golem or two.

 

Just like Snowy, I only protect villages if they have good offers. Iron Golems are the best way to protect them, but when you think about the cost to create them; it is pretty debatable if it is worth it or not.

 

Iron is quite common in the game, especially if you mine a lot during the night time. I think setting up a small barricade around villagers you want to keep and placing down a lot of torches is useful, if you're just starting out with little material and you already have spotted a village, but eventually you'll want to expand how you protect your village.

 

If we kill them others won't attack so we'll protect them 3

 

That's not really protecting villagers, and it seems counterintuitive since villagers are useful to trade with. Doing something little like getting a villager inside a building and blocking the door with some blocks (like cobblestone) seems better than just slaying the villagers, because at least you'll still have the ability to trade with them.

 

Actually, that's nice, to imprison and enslave. Interesting idea