Remember that that 26 inches is an estimate. If the babe carries their length in their legs, they'll last longer in the seat, and if they carry it in their torso, they won't last as long. The test is where their head is. When you don't have an inch of plastic above the baby's head, the seat has been outgrown. The feet have nothing to do with it. I mistakenly took my son out of his infant seat a full 6 months before he outgew it, because I thought they had to be taken out when their feet went over the end. I was wrong. :-D Oh well, such is life. It really is nice to be able to leave them in until they can sit up really well on their own. You will probably get a lot more time out of the seat than you think if you just watch the head and wait for there to be only about an inch of plastic above it. They really are that small when they're born. I looked at a sleeper from DS when he came home and held it up to him. The feet came to his tush. Wow, what a difference 16 months makes.