When me and my sibes are up in the mountain house, we let them freely off lead. They are 7 months. The first night, I didn't trust them therefore I tied them up to a tree with at 50ft leash if they were to be outside without supervision...somehow, the same night, they got loose. I went outside and they came running towards me..so who knows how far they went off lead. The family finally decided to let them off lead when they're outside. They do pretty good...we go hiking, they'll take off and come back within no more than 5min.
So to answer, will I let them off lead, I'll say yes in enclosed areas as well as the forest, or farm. But never in the city.