So baby's been here for a few months, and is growing like a weed. At some point you look at him and go, "hmmm, he's looking a little squished in his car seat!" and you have flashbacks to all the countless hours you spent researching and choosing the "perfect" seat, only to be faced with it again in just a few months! Not to worry--let's see if it really is time to move to the next step.
So how do you know if baby has outgrown his infant seat?
First, get an accurate weight, and make sure baby is still within the weight limits of his car seat. However, that's not the only thing to consider. It's also important to assess baby's height. Car seats have a stated height limit, but don't panic if baby has gone over that limit without you realizing it. Unlike the weight limit, the car seat's height limit is just a general guideline--it's not set in stone. A pretty common height limit is 30 inches, but some infants have long outgrown the seat at that point, while others have months to go. You want to be sure that there is at least an inch of hard shell above the baby's head. This is a great visual on how to measure.
If baby is getting close to the top of his car seat, it's time to start shopping for the next step: a rear-facing convertible.