A long time, I’d say!
In Facebook parenting groups and at babywearing meetups, a common question is, “What’s the weight limit for this carrier?” Looking at the instructions doesn’t really answer the intent behind that question, which is, “How long can I use this carrier? What’s the long-term value I can get out of it?”
Most carriers are tested and approved for 7-35 lbs, with some going higher. The average baby reaches that at about 4 years old—some earlier, some later. Whether your child likes to be carried a lot at 4 has something to do with what they’re used to doing and family choices—but more to do with their personality, as they learn to express their preferences as little growing people.
Either way, by around 4 years of age, you’ll have had the opportunity to get a lot of use and value out of your carrier. But does being tested to a certain weight guarantee comfort?
Finding a comfortable carrier is a combination of a lot of factors. Your own health is one of them—if you have circulation issues, for example, you may choose a carrier you know won’t dig in tightly. If your child has special needs as she grows, her safety and comfort with your carrier will affect the value and use you get out of it. The design of the carrier will make a big difference. A 30-lb one-year-old has much different proportions than a 30-lb four-year-old!
Finally, how you use the carrier will make a great difference in your comfort level. Newborns spend most of their time on us, where a preschooler might run wild all day at the zoo and only need a lift on the walk back to the parking lot. I’ve used a ring sling with a one-day-old newborn all the way up to a kindergartener, and while the kindergartener weighed more, he was on me less. Reframing the question to “Is using this carrier more comfortable than carrying my child in my arms?” made the decision easy—I always tossed my ring sling in the bottom of my purse, and more times than not, ended up using it!