I've seen a lot of people say they are making the switch to he convertible car seat "early", because their LO is so heavy to carry around in the infant seat.

Assuming baby isn't actually outgrowing the infant seat in height or weight, why not just keep using te infant seat but leave it in the car? It seems like it would be nice to have the option of lugging the seat and baby when you wanted even if you usually just strap them in and out in the car.

The two reasons I can think of are that the convertible is easier to get them in and out of while in the car, or it's more comfortable for the baby? Am I on the right track?