Babies in Restaurants

We have 7 month old twins and we take them to eat with us pretty often. We love going to breakfast on the weekends and are kind of "foodies". We've never had a problem with taking the twins into restaurants in their infant car seats but now that they are eating solids and sitting on their own I'm wondering when we should put them in a high chair and make them more a part of our meal. Occasionally they'll get fussy in their car seats so we take them out and if it's too bad we'll get our food to go because I really hate ruining others dining experience. I'm worried high chairs will make it harder to leave in a rush if we have to but I also can see it making them happier and less fussy. So when did you start using high chairs in restaurants?