I want to say about 20 minutes for one car, but I can't quite recall. They are very thorough. Although apparently my car & infant carseat were known to be a tough combo so maybe it took longer than usual.
When I do car seat checks it takes 15-40 mins depending on how hard the install is (car seat may be a hard seat or car seat and car just are hard together). That is per car. Also make sure they let you do it not just tell you. I have seen techs that install it and then tell the parents how to do it (I dont know what their techs do)
It takes about 20-30 mins, depending on your car and carseat. I have a Britax Marathon (common carseat) and it uses the latch system in my Lexus (pretty easy system for installation), so it didn't take that long. They make the appt for 1 hr to allow you to ask questions and for them to explain the whole installation process to you while they are doing it. It usually doesn't take a full hour though.
I want to say ours took an hour -- the tech was super thorough and we installed our snugride with and without it's base using both the center seat (using the seat belt) and the outside seat (using latch). If there aren't so many variables it would definitely be faster.
Re: Carseat check at lucile packard?