We take our girls out a lot, and always have. Currently they are 7yrs, 5yrs, and 2yrs. They have grown up going out and they know the rules, and they know the bonuses they get when we go out, and have learnt not to jepordise those bonuses (choosing their own meals, a milkshake or special kids drink, maybe dessert etc).
That been said, they have their days when we know they can't handle going out, so we don't.