Our carrier is 29 inches and 22lbs...but he's already 26 inches and a couple inches from the top. We'll probably switch in another month or two. Definitely before he reaches either maximum. Most babies outgrow the length first.
LO hasn't outgrown our carrier yet but we are switching within the next month because I don't ever carry her in the carrier anymore I always take her out and put her in the stroller or hold her anyways.
Technically, Jude still fit in his infant seat (Graco SafeSeat 30 lbs and 32 in) 9 months (he was 30 in and 22 lbs), but he was so uncomfortable in it. He would scream every car ride, so we switched.
Re: When did you, or have you, switched to a convertible car seat
Our infant carrier went to 29" and 22 lbs.
At 5 months, DS was 28" and 18lbs. We put a rear-facing convertible car seat in this past weekend.
LO hasn't outgrown our carrier yet but we are switching within the next month because I don't ever carry her in the carrier anymore I always take her out and put her in the stroller or hold her anyways.