Minecraft wiki entry for Villager, associated text: When a villager reaches its job site block, it commences "work". Two times a day, this action of working resupplies any locked trades. Villagers can resupply twice per day, even without having a bed or while sitting in a minecart. A villager can "reach" its job site block if the block is in any of the 8 directly adjacent or diagonal block spaces horizontally around it at the height of their feet, or at the 9 blocks below that. Villagers can still "reach" them diagonally, even if they can't see or touch the face of the block.