I've got three kids in car seats now. Princess is in a booster, Toddler is in a regular car seat and Peanut is in an infant. Our family vehicle at the moment is a large SUV. Because it is so tall, I half to climb into it to buckle anyone in. Princess is getting better at being able to buckle herself in, but about half of the time, she still needs help. To help her, I have to go to the other side of the SUV from where Toddler and Peanut are and climb into the vehicle. Peanut's car seat is an old infant carrier. I won't say how old, I might get in trouble. The SUV is too high and she is in on the drivers side which means I have to use my left hand to pull out the car seat. Because of the height of the SUV, I can't lift the car seat out. That means, when I'm alone out with the kids, I just have to take her out of the car seat and leave the car seat in the van. Not easy when you are going grocery shopping.
To get everyone in their seats and everyone out of their seats takes quite a bit of time. Everytime I'm dealing with this all I can do is grumble, I hate car seats.
Can you imagine sleeping like that? At least she is legally buckled in.